Materials Characterization最新文献_第3页

Generation of micrograph-annotation pairs for steel microstructure recognition using the hybrid deep generative model in the case of an extremely small and imbalanced dataset 在极小且不平衡的数据集中使用混合深度生成模型生成用于钢材微观结构识别的显微照片-注释对

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-23 DOI: 10.1016/j.matchar.2024.114407

Insufficient annotated samples coupled with class imbalance problem largely restrict the wide application of deep learning (DL)-based approach in microstructure recognition and quantification. In this work, we present a micrograph augmentation approach using the hybrid deep generative model to generate SEM image-annotation pairs for the establishment of a large-scale and well-balanced augmentation dataset. In this method, a generator is established to produce the desired annotations and then a translator is trained to translate these synthetic annotations into high-quality SEM images. The proposed method is successfully applied to an extremely small and imbalanced additively manufactured (AM) steel dataset containing only one SEM image-annotation pair with a very low martensite/austenite (MA) fraction, to significantly augment the initial dataset and achieve a more balanced distribution of phase fraction. The effectiveness of the present method is well demonstrated by the fact that the extensibility of microstructure recognition model to unseen micrographs is improved through the utilization of synthetic data. Furthermore, the impact of synthetic data proportion on the model's performance and the underlying reasons for synthetic data to improve the extensibility of trained models are also discussed in detail.

注释样本不足和类不平衡问题在很大程度上限制了基于深度学习（DL）的方法在显微结构识别和量化中的广泛应用。在这项工作中，我们提出了一种显微摄影增强方法，使用混合深度生成模型生成 SEM 图像-注释对，以建立大规模且均衡的增强数据集。在这种方法中，先建立一个生成器来生成所需的注释，然后训练一个翻译器将这些合成注释翻译成高质量的扫描电镜图像。所提出的方法成功地应用于一个极小且不平衡的加法制造（AM）钢数据集，该数据集仅包含一个马氏体/奥氏体（MA）分数极低的 SEM 图像-注释对，从而显著增强了初始数据集，并使相分数分布更加平衡。通过利用合成数据，显微结构识别模型对未见显微照片的可扩展性得到了改善，这充分证明了本方法的有效性。此外，还详细讨论了合成数据比例对模型性能的影响以及合成数据提高训练模型可扩展性的根本原因。

{"title":"Generation of micrograph-annotation pairs for steel microstructure recognition using the hybrid deep generative model in the case of an extremely small and imbalanced dataset","authors":"","doi":"10.1016/j.matchar.2024.114407","DOIUrl":"10.1016/j.matchar.2024.114407","url":null,"abstract":"<div><div>Insufficient annotated samples coupled with class imbalance problem largely restrict the wide application of deep learning (DL)-based approach in microstructure recognition and quantification. In this work, we present a micrograph augmentation approach using the hybrid deep generative model to generate SEM image-annotation pairs for the establishment of a large-scale and well-balanced augmentation dataset. In this method, a generator is established to produce the desired annotations and then a translator is trained to translate these synthetic annotations into high-quality SEM images. The proposed method is successfully applied to an extremely small and imbalanced additively manufactured (AM) steel dataset containing only one SEM image-annotation pair with a very low martensite/austenite (MA) fraction, to significantly augment the initial dataset and achieve a more balanced distribution of phase fraction. The effectiveness of the present method is well demonstrated by the fact that the extensibility of microstructure recognition model to unseen micrographs is improved through the utilization of synthetic data. Furthermore, the impact of synthetic data proportion on the model's performance and the underlying reasons for synthetic data to improve the extensibility of trained models are also discussed in detail.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigating scandium-alloyed NbSi systems: Microstructure, oxidation behavior, and fracture toughness 研究钪合金化铌硅体系：微观结构、氧化行为和断裂韧性

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-23 DOI: 10.1016/j.matchar.2024.114409

In order to synchronize the oxidation resistance and room temperature fracture toughness of NbSi based alloys to meet the development needs, the effects of Sc addition on microstructure evolution, oxidation resistance and mechanical performance of Nb-16Si-20Ti-1.5Zr-1C-1B-xSc (x = 0, 0.1, 0.3, 0.5, 0.8) alloys are studied systematically. All compositions of the alloys are composed of two phases, Nbss and γ-(Nb,X)₅Si₃, X-ray diffraction and electron microscopy reveal that Sc addition refines γ-(Nb,X)₅Si₃ phases and promotes a transition from primary to lamellar eutectic structures, enhancing oxidation resistance. Sc₂O₃ formation at phase boundaries impedes oxygen diffusion, forming continuous oxide barriers (TiO₂ and SiO₂), thereby improving oxidation resistance. Mechanical testing shows an increase in fracture toughness with Sc doping, attributed to enhanced crack deflection and energy absorption within the Nbss phase. These results are important for the simultaneous improvement of room-temperature fracture toughness and high-temperature oxidation resistance as well as the mechanism of action of the rare earth element Sc, and for the further development of NbSi based superalloys to meet practical needs.

为了使 NbSi 基合金的抗氧化性和室温断裂韧性同步发展，系统研究了添加 Sc 对 Nb-16Si-20Ti-1.5Zr-1C-1B-xSc (x = 0, 0.1, 0.3, 0.5, 0.8) 合金的微观结构演变、抗氧化性和力学性能的影响。X 射线衍射和电子显微镜显示，Sc 的加入细化了 γ-(Nb,X)5Si3 相，并促进了从原生结构到片状共晶结构的转变，从而增强了抗氧化性。在相界形成的 Sc2O3 会阻碍氧气扩散，形成连续的氧化物屏障（TiO2 和 SiO2），从而提高抗氧化性。机械测试表明，掺杂 Sc 后断裂韧性增加，这归因于 Nbss 相内裂纹偏转和能量吸收的增强。这些结果对于同时提高室温断裂韧性和高温抗氧化性以及稀土元素 Sc 的作用机理，以及进一步开发 NbSi 基超耐热合金以满足实际需求具有重要意义。

{"title":"Investigating scandium-alloyed NbSi systems: Microstructure, oxidation behavior, and fracture toughness","authors":"","doi":"10.1016/j.matchar.2024.114409","DOIUrl":"10.1016/j.matchar.2024.114409","url":null,"abstract":"<div><div>In order to synchronize the oxidation resistance and room temperature fracture toughness of Nb<img>Si based alloys to meet the development needs, the effects of Sc addition on microstructure evolution, oxidation resistance and mechanical performance of Nb-16Si-20Ti-1.5Zr-1C-1B-<em>x</em>Sc (<em>x</em> = 0, 0.1, 0.3, 0.5, 0.8) alloys are studied systematically. All compositions of the alloys are composed of two phases, Nbss and γ-(Nb,X)<sub>5</sub>Si<sub>3</sub>, X-ray diffraction and electron microscopy reveal that Sc addition refines γ-(Nb,X)<sub>5</sub>Si<sub>3</sub> phases and promotes a transition from primary to lamellar eutectic structures, enhancing oxidation resistance. Sc<sub>2</sub>O<sub>3</sub> formation at phase boundaries impedes oxygen diffusion, forming continuous oxide barriers (TiO<sub>2</sub> and SiO<sub>2</sub>), thereby improving oxidation resistance. Mechanical testing shows an increase in fracture toughness with Sc doping, attributed to enhanced crack deflection and energy absorption within the Nbss phase. These results are important for the simultaneous improvement of room-temperature fracture toughness and high-temperature oxidation resistance as well as the mechanism of action of the rare earth element Sc, and for the further development of Nb<img>Si based superalloys to meet practical needs.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of temperature on creep aging behavior of the nugget zone of AA2195 AlLi alloy produced by friction stir welding 温度对搅拌摩擦焊生产的 AA2195 AlLi 合金金块区蠕变时效行为的影响

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-23 DOI: 10.1016/j.matchar.2024.114408

This paper aims to study the effect of temperatures on the creep aging behaviors of the nugget zone (NZ) of AlLi alloy by friction stir welding (FSW). The results suggest that the creep strain of the NZ experiences a significant increase as the temperature rises, surpassing that of the base material (BM) at equivalent temperatures. In the case of NZ, the elevation of temperature from 160 to 190 °C induces a pronounced increase in both the size and volume fraction of the T₁ phase, which results in a substantial enhancement in the strength. In contrast, the peak-aged strengths of the BM exhibit minimal variation in this temperature range. As the temperature increases, the time required for the BM to reach its peak aging state significantly decreases, whereas the changes in the NZ are less pronounced. For the NZ, the time required to reach the peak aging state is obviously longer than that for the BM. Although the average length of the T₁ phase in the NZ is markedly greater than that in the BM, its volume fraction and number density in the NZ are considerably lower than those in the BM, resulting in inferior strength reinforcement in the NZ compared to the BM after creep aging.

本文旨在研究温度对搅拌摩擦焊（FSW）铝锂合金金块区（NZ）蠕变时效行为的影响。结果表明，随着温度的升高，NZ 的蠕变应变显著增加，超过了同等温度下母材（BM）的蠕变应变。就 NZ 而言，温度从 160 °C 升至 190 °C 会导致 T1 相的尺寸和体积分数明显增加，从而大幅提高强度。相比之下，BM 的峰值老化强度在此温度范围内变化极小。随着温度的升高，BM 达到峰值老化状态所需的时间明显缩短，而 NZ 的变化则不太明显。就 NZ 而言，达到峰值老化状态所需的时间明显长于 BM。虽然 NZ 中 T1 相的平均长度明显大于 BM 中的 T1 相，但 NZ 中 T1 相的体积分数和数量密度却大大低于 BM 中的 T1 相，导致 NZ 在蠕变老化后的强度强化效果不如 BM。

{"title":"Effect of temperature on creep aging behavior of the nugget zone of AA2195 AlLi alloy produced by friction stir welding","authors":"","doi":"10.1016/j.matchar.2024.114408","DOIUrl":"10.1016/j.matchar.2024.114408","url":null,"abstract":"<div><div>This paper aims to study the effect of temperatures on the creep aging behaviors of the nugget zone (NZ) of Al<img>Li alloy by friction stir welding (FSW). The results suggest that the creep strain of the NZ experiences a significant increase as the temperature rises, surpassing that of the base material (BM) at equivalent temperatures. In the case of NZ, the elevation of temperature from 160 to 190 °C induces a pronounced increase in both the size and volume fraction of the T<sub>1</sub> phase, which results in a substantial enhancement in the strength. In contrast, the peak-aged strengths of the BM exhibit minimal variation in this temperature range. As the temperature increases, the time required for the BM to reach its peak aging state significantly decreases, whereas the changes in the NZ are less pronounced. For the NZ, the time required to reach the peak aging state is obviously longer than that for the BM. Although the average length of the T<sub>1</sub> phase in the NZ is markedly greater than that in the BM, its volume fraction and number density in the NZ are considerably lower than those in the BM, resulting in inferior strength reinforcement in the NZ compared to the BM after creep aging.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Solute-induced transition in Poisson's ratio and strength: A phenomenon in additively manufactured Al-Si-Mg alloys 溶质诱导的泊松比和强度转变：添加式制造的铝硅镁合金中的一种现象

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-22 DOI: 10.1016/j.matchar.2024.114384

In this study, cubic coupons of AlSi10Mg alloy were printed using the laser powder bed fusion (LPBF) technique. The effect of heating/reheating cycles on solute trapping and partitioning of alloying elements was investigated using atom probe tomography and transmission electron microscopy. Nano-hardness analysis and uniaxial tensile tests equipped with digital image correlation were employed to investigate the mechanical properties and Poisson's ratio. X-ray micro-computed tomography was utilized to detect strain localization sites along the building direction. Also, the uniaxial tensile test was simulated using finite element analysis to verify the experimental data and predict stress triaxiality. The results showed that the solute trapping and partitioning during the LPBF process results in remarkable changes in phases, their size and morphology, Poisson's ratio, strengthening factor, and consequently mechanical properties. While the tensile sample from top part of the LPBF coupon mostly shows porosity due to floating and entrapment of gases during layer-by-layer fusion/solidification, the sample from bottom part is exposed to sub-surface microcracking induced by residual stresses. The hardness, elastic, and shear moduli, Peierls stress, and cumulative strain energy of the top-part sample are higher than those of the bottom-part sample even though electron backscatter diffraction analyses report similar grain size and texture. Besides, by distancing from the build plate, the Poisson's ratio decreases. Simulation results of both samples indicate that the middle of the gauge is a high-potential area of failure initiation, where the bottom-part sample shows higher stress localization.

在这项研究中，使用激光粉末床熔融（LPBF）技术打印了 AlSi10Mg 合金立方体试样。利用原子探针断层扫描和透射电子显微镜研究了加热/再加热循环对溶质捕获和合金元素分配的影响。采用纳米硬度分析和配备数字图像相关技术的单轴拉伸试验来研究机械性能和泊松比。利用 X 射线微型计算机断层扫描来检测沿建筑方向的应变定位点。此外，还利用有限元分析模拟了单轴拉伸试验，以验证实验数据并预测应力三轴性。结果表明，在 LPBF 过程中，溶质截留和分配导致相、相的大小和形态、泊松比、强化因子以及机械性能发生显著变化。LPBF 试样上部的拉伸试样大多因逐层熔融/凝固过程中气体的漂浮和夹带而出现孔隙，而下部的试样则因残余应力而出现表层下的微裂纹。尽管电子反向散射衍射分析显示出相似的晶粒尺寸和纹理，但上部样品的硬度、弹性和剪切模量、Peierls 应力以及累积应变能均高于下部样品。此外，与构建板的距离越远，泊松比越小。两种样品的模拟结果表明，量规的中部是失效的高发区，而底部样品的应力定位更高。

{"title":"Solute-induced transition in Poisson's ratio and strength: A phenomenon in additively manufactured Al-Si-Mg alloys","authors":"","doi":"10.1016/j.matchar.2024.114384","DOIUrl":"10.1016/j.matchar.2024.114384","url":null,"abstract":"<div><div>In this study, cubic coupons of AlSi10Mg alloy were printed using the laser powder bed fusion (LPBF) technique. The effect of heating/reheating cycles on solute trapping and partitioning of alloying elements was investigated using atom probe tomography and transmission electron microscopy. Nano-hardness analysis and uniaxial tensile tests equipped with digital image correlation were employed to investigate the mechanical properties and Poisson's ratio. X-ray micro-computed tomography was utilized to detect strain localization sites along the building direction. Also, the uniaxial tensile test was simulated using finite element analysis to verify the experimental data and predict stress triaxiality. The results showed that the solute trapping and partitioning during the LPBF process results in remarkable changes in phases, their size and morphology, Poisson's ratio, strengthening factor, and consequently mechanical properties. While the tensile sample from top part of the LPBF coupon mostly shows porosity due to floating and entrapment of gases during layer-by-layer fusion/solidification, the sample from bottom part is exposed to sub-surface microcracking induced by residual stresses. The hardness, elastic, and shear moduli, Peierls stress, and cumulative strain energy of the top-part sample are higher than those of the bottom-part sample even though electron backscatter diffraction analyses report similar grain size and texture. Besides, by distancing from the build plate, the Poisson's ratio decreases. Simulation results of both samples indicate that the middle of the gauge is a high-potential area of failure initiation, where the bottom-part sample shows higher stress localization.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Si-doped BCC-based high-entropy alloy to overcome soft magnetic–mechanical properties trade-off via coherent B2 nanoprecipitates 通过相干 B2 纳米沉淀物克服软磁机械特性权衡的掺硅 BCC 基高熵合金

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-21 DOI: 10.1016/j.matchar.2024.114402

The trade-off between magnetic property and mechanical property usually occurs in traditional soft magnetic materials (SMMs) because the strengthening strategy (e.g. precipitation hardening) can worsen soft magnetic properties through the hindrance of magnetic domain wall motion. This dilemma is overcome in current work by developing the FeCoNiAlSi_0.01 (Fe_24.94Co_24.94Ni_24.94Al_24.94Si_0.24 in at.%) high-entropy alloy (HEA) (termed as Si0.24 HEA) with excellent soft magnetic performance and attractive mechanical property through coherent B2 nanoprecipitates (6 nm) distributed in body-centered-cubic (BCC) matrix. The atom probe tomography (APT) result shows that the B2 nanoprecipitates have similar composition to the BCC matrix. The Si0.24 HEA shows small width of domain branching and low anisotropy constant leading to the optimum alternating current (AC) soft magnetic properties. The respective total loss (AC P_s), the coercivity (AC H_c), and the eddy current loss (P_e) at 950 Hz of the Si0.24 HEA are 21.20 W/kg, 230 A/m, and 16.25 W/kg, which is reduced by 45 %, 44 %, and 48 % compared with the FeCoNiAl (Si-free HEA). The Si0.24 HEA shows good mechanical property with the yield strength of 987 MPa and engineering strain of 30 %, which is 12 % and 1.3 times higher than that of the Si-free HEA. Moreover, the current studied HEAs exhibit high saturation magnetization (M_s = 108–115 Am²/kg) and Curie temperature (T_C = 1053–1097 K, larger than T_C of Fe (1043 K)), which indicates their perspective high-temperature applications as novel SMMs for the need of modern power electronics and electrical machines.

传统的软磁材料（SMMs）通常会在磁性能和机械性能之间进行权衡，因为强化策略（如沉淀硬化）会阻碍磁畴壁的运动，从而恶化软磁性能。目前的研究克服了这一难题，通过在体心立方体（BCC）基体中分布相干的 B2 纳米沉淀物（6 nm），开发出了具有优异软磁性能和诱人机械性能的 FeCoNiAlSi0.01 (Fe24.94Co24.94Ni24.94Al24.94Si0.24 in at.%) 高熵合金（HEA）（称为 Si0.24 HEA）。原子探针断层扫描（APT）结果表明，B2 纳米沉淀物的成分与 BCC 基体相似。Si0.24 HEA 显示出较小的畴分支宽度和较低的各向异性常数，因而具有最佳的交流软磁特性。在 950 Hz 频率下，Si0.24 HEA 的总损耗（交流 Ps）、矫顽力（交流 Hc）和涡流损耗（Pe）分别为 21.20 W/kg、230 A/m 和 16.25 W/kg，与 FeCoNiAl（无硅 HEA）相比，分别降低了 45%、44% 和 48%。Si0.24 HEA 具有良好的机械性能，屈服强度为 987 兆帕，工程应变为 30%，分别是无硅 HEA 的 12% 和 1.3 倍。此外，目前研究的 HEA 表现出较高的饱和磁化率（Ms = 108-115 Am2/kg）和居里温度（TC = 1053-1097 K，高于铁的居里温度（1043 K）），这表明它们可在高温下作为新型 SMM 应用，以满足现代电力电子和电机的需要。

{"title":"The Si-doped BCC-based high-entropy alloy to overcome soft magnetic–mechanical properties trade-off via coherent B2 nanoprecipitates","authors":"","doi":"10.1016/j.matchar.2024.114402","DOIUrl":"10.1016/j.matchar.2024.114402","url":null,"abstract":"<div><div>The trade-off between magnetic property and mechanical property usually occurs in traditional soft magnetic materials (SMMs) because the strengthening strategy (e.g. precipitation hardening) can worsen soft magnetic properties through the hindrance of magnetic domain wall motion. This dilemma is overcome in current work by developing the FeCoNiAlSi<sub>0.01</sub> (Fe<sub>24.94</sub>Co<sub>24.94</sub>Ni<sub>24.94</sub>Al<sub>24.94</sub>Si<sub>0.24</sub> in at.%) high-entropy alloy (HEA) (termed as Si0.24 HEA) with excellent soft magnetic performance and attractive mechanical property through coherent B2 nanoprecipitates (6 nm) distributed in body-centered-cubic (BCC) matrix. The atom probe tomography (APT) result shows that the B2 nanoprecipitates have similar composition to the BCC matrix. The Si0.24 HEA shows small width of domain branching and low anisotropy constant leading to the optimum alternating current (AC) soft magnetic properties. The respective total loss (AC P<sub>s</sub>), the coercivity (AC H<sub>c</sub>), and the eddy current loss (P<sub>e</sub>) at 950 Hz of the Si0.24 HEA are 21.20 W/kg, 230 A/m, and 16.25 W/kg, which is reduced by 45 %, 44 %, and 48 % compared with the FeCoNiAl (Si-free HEA). The Si0.24 HEA shows good mechanical property with the yield strength of 987 MPa and engineering strain of 30 %, which is 12 % and 1.3 times higher than that of the Si-free HEA. Moreover, the current studied HEAs exhibit high saturation magnetization (M<sub>s</sub> = 108–115 Am<sup>2</sup>/kg) and Curie temperature (T<sub>C</sub> = 1053–1097 K, larger than T<sub>C</sub> of Fe (1043 K)), which indicates their perspective high-temperature applications as novel SMMs for the need of modern power electronics and electrical machines.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Altered microstructure, phase transformation behaviors and shape memory response of CuAlMn shape memory alloys fabricated by selective laser melting 通过选择性激光熔化制造的铜铝锰形状记忆合金的微观结构、相变行为和形状记忆响应的改变

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-21 DOI: 10.1016/j.matchar.2024.114398

In this paper, nearly defect-free CuAlMn SMAs were successfully fabricated by selected laser melting (SLM). The result of microstructure show that only one type of thermal-induced martensite was detected in the prepared specimens, and the process parameters play a vital role in phase transformation behaviors. The alloy shows excellent ultimate tensile strength of 820 MPa and elongation of 11.5 %. Furthermore, the high shape memory response, i.e. shape recovery rate of 91.4 %–99.6 %, shape memory strain of 2.59 %–5.46 %, was presented under compressive strain not exceeding 8 %.

本文采用选择性激光熔化（SLM）技术成功制备了几乎无缺陷的铜铝锰 SMA。显微组织结果表明，在制备的试样中只检测到一种热诱导马氏体，而工艺参数对相变行为起着至关重要的作用。该合金的极限拉伸强度为 820 兆帕，伸长率为 11.5%。此外，在抗压应变不超过 8 % 的情况下，该合金具有较高的形状记忆响应，即形状恢复率为 91.4 %-99.6 %，形状记忆应变为 2.59 %-5.46 %。

引用次数: 0

In-situ EBSD study of the active slip systems and substructure evolution in a medium-entropy alloy during tensile deformation 拉伸变形过程中中等熵合金活性滑移系统和亚结构演变的原位 EBSD 研究

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-21 DOI: 10.1016/j.matchar.2024.114405

Electron backscatter diffraction (EBSD) coupled with in-situ tensile loading is powerful for investigating the microstructural evolution of alloys. Thermo-mechanically treated f.c.c. medium-entropy alloys (MEAs) typically have high densities of annealing twin boundaries (ATBs), which can not only strengthen but also toughen the MEA via interacting with dislocations. However, the evolution of ATBs and other substructures in plastically-deformed MEA has not yet been revealed. Plastic deformation involving dislocation evolution, active slip systems, lattice rotation, boundary transformation, and grain subdivision in a polycrystalline MEA Ni_41.4Co_23.3Cr_23.3Al₃Ti₃V₆ was studied using in-situ EBSD. The slip was accompanied by heterogeneous lattice rotation among grains and within grains, where inhomogeneous plasticity was accommodated by geometrically-necessary dislocations (GNDs). Both GND and low-angled boundaries (LABs) densities substantially increased with progressive strain, which was mainly concentrated in sites approaching ATBs or grain boundaries (GBs). Located stress, lattice rotation, or curvature caused a loss in the coherence of ATBs, which resulted in integrity loss with increasing strain and promoted a decrease in density by 60 %. Further, lattice rotation incompatibility due to constraints from neighboring grains leads to grain fragmentation into various misorientated volumes, which were separated by LABs or high-angle boundaries (HABs). The grain orientation angle increased with progressive strain and crystallographic 〈111〉 orientation gradually spread toward a tensile direction. Slip systems with maximum Schmid factor were activated first at ε ≥ 3.9 %, which is almost the same with experimental slip traces. Both single slip and double slip occurred during plasticity, where straight slip traces tend to curve due to lattice curvature. Slip transfers are not only controlled by geometric compatibility factor, which can occur between some neighboring grains with low geometric compatibility factor but high Schmid factor.

电子反向散射衍射 (EBSD) 与原位拉伸加载相结合，可用于研究合金的微观结构演变。经过热机械处理的 f.c.c. 中等熵合金 (MEA) 通常具有高密度的退火孪晶边界 (ATB)，通过与位错的相互作用，ATB 不仅可以增强 MEA 的强度，还可以使 MEA 更坚韧。然而，ATB 和其他亚结构在塑性变形 MEA 中的演变尚未揭示。利用原位 EBSD 研究了多晶 MEA Ni41.4Co23.3Cr23.3Al3Ti3V6 中涉及位错演变、主动滑移系统、晶格旋转、边界转变和晶粒细分的塑性变形。滑移伴随着晶粒间和晶粒内的异质晶格旋转，其中的非均质塑性由几何必要位错（GND）所容纳。随着应变的逐渐增加，GND 和低角度边界（LABs）密度都大幅增加，主要集中在接近 ATB 或晶粒边界（GBs）的位置。定位应力、晶格旋转或曲率会导致 ATB 的一致性丧失，从而导致完整性随应变增加而丧失，并使密度降低 60%。此外，由于受到邻近晶粒的限制，晶格旋转不相容，导致晶粒破碎成各种错向体积，这些错向体积被 LAB 或高角度边界 (HAB) 分隔开来。晶粒取向角随着应变的增加而增大，晶体学〈111〉取向逐渐向拉伸方向扩散。具有最大施密特因子的滑移系统首先在 ε ≥ 3.9 % 时被激活，这与实验滑移轨迹基本一致。在塑性过程中出现了单滑移和双滑移，其中直线滑移轨迹由于晶格曲率而趋于弯曲。滑移转移不仅受几何相容性因子的控制，在一些几何相容性因子低但施密德因子高的相邻晶粒之间也会发生滑移转移。

{"title":"In-situ EBSD study of the active slip systems and substructure evolution in a medium-entropy alloy during tensile deformation","authors":"","doi":"10.1016/j.matchar.2024.114405","DOIUrl":"10.1016/j.matchar.2024.114405","url":null,"abstract":"<div><div>Electron backscatter diffraction (EBSD) coupled with in-situ tensile loading is powerful for investigating the microstructural evolution of alloys. Thermo-mechanically treated f.c.c. medium-entropy alloys (MEAs) typically have high densities of annealing twin boundaries (ATBs), which can not only strengthen but also toughen the MEA via interacting with dislocations. However, the evolution of ATBs and other substructures in plastically-deformed MEA has not yet been revealed. Plastic deformation involving dislocation evolution, active slip systems, lattice rotation, boundary transformation, and grain subdivision in a polycrystalline MEA Ni<sub>41.4</sub>Co<sub>23.3</sub>Cr<sub>23.3</sub>Al<sub>3</sub>Ti<sub>3</sub>V<sub>6</sub> was studied using in-situ EBSD. The slip was accompanied by heterogeneous lattice rotation among grains and within grains, where inhomogeneous plasticity was accommodated by geometrically-necessary dislocations (GNDs). Both GND and low-angled boundaries (LABs) densities substantially increased with progressive strain, which was mainly concentrated in sites approaching ATBs or grain boundaries (GBs). Located stress, lattice rotation, or curvature caused a loss in the coherence of ATBs, which resulted in integrity loss with increasing strain and promoted a decrease in density by 60 %. Further, lattice rotation incompatibility due to constraints from neighboring grains leads to grain fragmentation into various misorientated volumes, which were separated by LABs or high-angle boundaries (HABs). The grain orientation angle increased with progressive strain and crystallographic 〈111〉 orientation gradually spread toward a tensile direction. Slip systems with maximum Schmid factor were activated first at ε ≥ 3.9 %, which is almost the same with experimental slip traces. Both single slip and double slip occurred during plasticity, where straight slip traces tend to curve due to lattice curvature. Slip transfers are not only controlled by geometric compatibility factor, which can occur between some neighboring grains with low geometric compatibility factor but high Schmid factor.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cryogenic tribological behavior of coarse, ultrafine grained and heterogeneous Fe-18Cr-8Ni austenitic stainless steel 粗晶粒、超细晶粒和异质 Fe-18Cr-8Ni 奥氏体不锈钢的低温摩擦学行为

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-21 DOI: 10.1016/j.matchar.2024.114406

Commonly used austenitic stainless steels (ASSs) have some limitation in sliding wear conditions due to their relatively low yield strength and hardness. To improve the wear resistance, three kinds of microstructure (coarse grain (CG), heterogeneous structure (HS), and ultrafine grain (UFG)) are prepared, to investigate the grain size on the dry sliding tribological behavior, as well as wear mechanisms of Fe-18Cr-8Ni ASSs at room temperature (RT) and cryogenic temperature (−120 °C). The results indicate that at RT the UFG specimen exhibits the lowest wear rate during the wear tests, where the wear mechanisms are mainly oxidation wear and abrasive wear. While, when tested at −120 °C, the CG specimen exhibits the best wear resistance compared with that of the other two specimens due to its superior plastic deformation ability and strain hardening ability. Moreover, the HS specimen exhibits the lowest coefficient of friction (CoF), which is due to the abrasive particles generated on the contact surface provide a certain level of friction reduction, while the wear rate increases as these particles serve as third-party abrasives, which further removing material.

由于屈服强度和硬度相对较低，常用的奥氏体不锈钢（ASS）在滑动磨损条件下具有一定的局限性。为了提高耐磨性，研究人员制备了三种微观结构（粗晶粒 (CG)、异质结构 (HS) 和超细晶粒 (UFG)），以研究晶粒大小对 Fe-18Cr-8Ni ASS 在室温 (RT) 和低温 (-120 °C) 下的干滑动摩擦行为以及磨损机理的影响。结果表明，在室温下，UFG 试样在磨损试验中的磨损率最低，磨损机制主要是氧化磨损和磨料磨损。而在 -120 ℃ 下进行测试时，CG 试样由于其优异的塑性变形能力和应变硬化能力，与其他两种试样相比表现出最佳的耐磨性。此外，HS 试样的摩擦系数（CoF）最低，这是由于接触面上产生的磨料颗粒在一定程度上减少了摩擦，而这些颗粒作为第三方磨料，进一步去除材料，从而增加了磨损率。

{"title":"Cryogenic tribological behavior of coarse, ultrafine grained and heterogeneous Fe-18Cr-8Ni austenitic stainless steel","authors":"","doi":"10.1016/j.matchar.2024.114406","DOIUrl":"10.1016/j.matchar.2024.114406","url":null,"abstract":"<div><div>Commonly used austenitic stainless steels (ASSs) have some limitation in sliding wear conditions due to their relatively low yield strength and hardness. To improve the wear resistance, three kinds of microstructure (coarse grain (CG), heterogeneous structure (HS), and ultrafine grain (UFG)) are prepared, to investigate the grain size on the dry sliding tribological behavior, as well as wear mechanisms of Fe-18Cr-8Ni ASSs at room temperature (RT) and cryogenic temperature (−120 °C). The results indicate that at RT the UFG specimen exhibits the lowest wear rate during the wear tests, where the wear mechanisms are mainly oxidation wear and abrasive wear. While, when tested at −120 °C, the CG specimen exhibits the best wear resistance compared with that of the other two specimens due to its superior plastic deformation ability and strain hardening ability. Moreover, the HS specimen exhibits the lowest coefficient of friction (CoF), which is due to the abrasive particles generated on the contact surface provide a certain level of friction reduction, while the wear rate increases as these particles serve as third-party abrasives, which further removing material.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-temperature sliding wear behavior of high-Mn heat-resistant alloys reinforced by different second-phase particles at 1073 K 不同第二相颗粒强化的高锰耐热合金在 1073 K 下的高温滑动磨损行为

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-21 DOI: 10.1016/j.matchar.2024.114404

High-temperature sliding wear behavior of Cr₂B-, TiC-, and TiB₂-reinforced high-Mn heat-resistant alloys, as well as the base alloy, is thoroughly investigated at 1073 K, along with the underlying mechanisms. The superior high-temperature wear resistance of the particle-reinforced alloys is primarily attributed to the introduction of second-phase particles, which improves the hardness and stability of the glaze layer on the wear track surface and enhances the resistance to high-temperature plastic deformation of the substrate, leading to a reduction in the coefficient of friction and wear rate. The TiB₂-reinforced alloy exhibits the most exceptional high-temperature wear resistance. These findings provide a new strategy for the design of high performance wear- and heat-resistant alloys.

在 1073 K 下对 Cr2B、TiC 和 TiB2 增强高锰耐热合金以及基合金的高温滑动磨损行为及其机理进行了深入研究。颗粒增强合金具有优异的高温耐磨性，这主要归功于第二相颗粒的引入，第二相颗粒提高了磨损轨迹表面釉层的硬度和稳定性，增强了基体的高温塑性变形阻力，从而降低了摩擦系数和磨损率。TiB2 增强合金表现出最优异的耐高温磨损性。这些发现为设计高性能耐磨耐热合金提供了一种新策略。

引用次数: 0

Effect of thermomechanical processing on the grain boundary character distribution of phosphorus bronze 热机械加工对磷青铜晶界特征分布的影响

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization

Pub Date : 2024-09-21 DOI: 10.1016/j.matchar.2024.114401

Grain boundary engineering (GBE) is widely adopted to improve the grain boundary (GB) character distribution (GBCD) of face-centered-cubic (FCC) metals. In phosphorus bronze alloy, achieving an optimized GBCD while maintaining sufficiently small grain size is critical for maintaining high strength and excellent bending workability. However, the precise evolution and formation mechanisms of GBs during GBE remain unclear to date. Leveraging electron backscatter diffraction and transmission electron microscopy analyses, this study examined the effect of thermomechanical processing (TMP) on GBCD optimization and twin-related domain (TRD) evolution in phosphorus bronze. The results revealed that strain-induced boundary migration (SIBM) plays a pivotal role in GBCD optimization. In particular, SIBM facilitates the formation of abundant new Σ3 boundaries behind migrating GB fronts, thus increasing the proportion of special boundaries (SBs) and introducing low-energy segments such as Σ9 and Σ27 boundaries. These boundaries effectively disrupt the connectivity of the random high angle grain boundary (RHAGB) network. Furthermore, the results indicate that the optimal TMP conditions for GBCD optimization include a reduction level of 5 %, annealing temperature of 450 °C, and annealing duration of 1 h. These conditions result in an average grain size being <3 μm and the GB fractions f_SBs and f_Σ9+Σ27 being 81.3 % and 9.8 %, respectively. Deformation twins formed within the deformed microstructure inhibit TRD growth, thus hindering GBCD optimization. Additionally, the optimal strain threshold for GBCD optimization lies near the strain threshold for the formation of deformation twins. TRDs form during the primary recrystallization process, while high-order twin boundaries form behind the migration front during the growth process.

晶界工程（GBE）被广泛用于改善面心立方体（FCC）金属的晶界特征分布（GBCD）。在磷青铜合金中，实现优化的 GBCD 同时保持足够小的晶粒尺寸对于保持高强度和优异的弯曲加工性至关重要。然而，迄今为止，GBE 过程中 GB 的精确演变和形成机制仍不清楚。本研究利用电子反向散射衍射和透射电子显微镜分析，研究了热机械加工（TMP）对磷青铜中 GBCD 优化和孪生相关畴（TRD）演化的影响。研究结果表明，应变诱导边界迁移（SIBM）在 GBCD 优化中起着关键作用。特别是，应变诱导边界迁移有利于在迁移的 GB 锋面后形成大量新的Σ3 边界，从而增加了特殊边界（SB）的比例，并引入了Σ9 和Σ27 边界等低能段。这些边界有效地破坏了随机高角度晶界（RHAGB）网络的连通性。此外，研究结果表明，优化 GBCD 的最佳 TMP 条件包括：还原度为 5%、退火温度为 450 °C、退火持续时间为 1 小时。在这些条件下，平均晶粒大小为 3 μm，GB 分数 fSBs 和 fΣ9+Σ27 分别为 81.3% 和 9.8%。变形微结构中形成的变形孪晶抑制了 TRD 的生长，从而阻碍了 GBCD 的优化。此外，GBCD 优化的最佳应变阈值位于变形孪晶形成的应变阈值附近。TRD 在初级再结晶过程中形成，而高阶孪晶边界则在生长过程中的迁移前沿后方形成。

{"title":"Effect of thermomechanical processing on the grain boundary character distribution of phosphorus bronze","authors":"","doi":"10.1016/j.matchar.2024.114401","DOIUrl":"10.1016/j.matchar.2024.114401","url":null,"abstract":"<div><div>Grain boundary engineering (GBE) is widely adopted to improve the grain boundary (GB) character distribution (GBCD) of face-centered-cubic (FCC) metals. In phosphorus bronze alloy, achieving an optimized GBCD while maintaining sufficiently small grain size is critical for maintaining high strength and excellent bending workability. However, the precise evolution and formation mechanisms of GBs during GBE remain unclear to date. Leveraging electron backscatter diffraction and transmission electron microscopy analyses, this study examined the effect of thermomechanical processing (TMP) on GBCD optimization and twin-related domain (TRD) evolution in phosphorus bronze. The results revealed that strain-induced boundary migration (SIBM) plays a pivotal role in GBCD optimization. In particular, SIBM facilitates the formation of abundant new Σ3 boundaries behind migrating GB fronts, thus increasing the proportion of special boundaries (SBs) and introducing low-energy segments such as Σ9 and Σ27 boundaries. These boundaries effectively disrupt the connectivity of the random high angle grain boundary (RHAGB) network. Furthermore, the results indicate that the optimal TMP conditions for GBCD optimization include a reduction level of 5 %, annealing temperature of 450 °C, and annealing duration of 1 h. These conditions result in an average grain size being <3 μm and the GB fractions <em>f</em><sub>SBs</sub> and <em>f</em><sub>Σ9+Σ27</sub> being 81.3 % and 9.8 %, respectively. Deformation twins formed within the deformed microstructure inhibit TRD growth, thus hindering GBCD optimization. Additionally, the optimal strain threshold for GBCD optimization lies near the strain threshold for the formation of deformation twins. TRDs form during the primary recrystallization process, while high-order twin boundaries form behind the migration front during the growth process.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0