Journal of Alloys and Metallurgical Systems最新文献

Effect of minor addition of silicon on deformation behaviour and texture evolution in CrFeNi medium entropy alloy 少量添加硅对CrFeNi中熵合金变形行为和织构演化的影响

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-12-01 DOI: 10.1016/j.jalmes.2024.100133

Swati Mahato , Tirupati Dhidhi , Nilesh P. Gurao , Krishanu Biswas

The present investigation systematically explores the effect of a minor addition of silicon on the microstructure, texture, and mechanical properties of FCC CrFeNi medium entropy alloy during rolling at room temperature. The addition of 2 at% Si in CrFeNi alloy results in the reduction of stacking fault energy from 22.4 mJ/m² for CrFeNi to 18.6 mJ/m² for (CrFeNi)₉₈Si₂ alloy. Bulk texture analysis reveals the presence of Brass and Goss texture components in the 90 % rolled samples. Microtextural study reveals that in CrFeNi and (CrFeNi)₉₈Si₂ alloy, Goss-orientated grains exhibit greater stability throughout the deformation compared to Cu-oriented grains. In addition to twinning, profuse shear banding was observed in both alloys at 90 % rolling reduction. The mechanical properties of homogenised (CrFeNi)₉₈Si₂ alloy demonstrate the enhanced combination of yield strength and hardness due to improved solid solution strengthening and dislocation strengthening accompanied by a marginal decrease in ductility due to twinning-induced strain hardening. While in 90 % rolled CrFeNi and (CrFeNi)₉₈Si₂ alloy, both yield strength and ultimate tensile strength increase drastically due to enhanced solid solution and dislocation strengthening though with a significant decrease in ductility.

本研究系统地探讨了少量添加硅对FCC CrFeNi中熵合金室温轧制过程中组织、织构和力学性能的影响。（CrFeNi）98Si2合金的层错能从（CrFeNi）的22.4 mJ/m2降低到（CrFeNi）的18.6 mJ/m2。整体织构分析表明，在90% %的轧制样品中存在黄铜和高斯织构成分。显微组织研究表明，在CrFeNi和（CrFeNi）98Si2合金中，goss取向晶粒在整个变形过程中表现出比cu取向晶粒更大的稳定性。除了孪晶外，两种合金在90% %轧制压下均出现大量剪切带。均匀化（CrFeNi）98Si2合金的力学性能表现为屈服强度和硬度的提高，这是由于固溶强化和位错强化的改善，同时由于孪晶引起的应变硬化，塑性略有下降。而在90% %轧制的CrFeNi和（CrFeNi）98Si2合金中，屈服强度和极限抗拉强度由于固溶和位错强化的增强而显著提高，但塑性显著降低。

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引用次数: 0

Influence of heat treatment time on microstructure evolution of austempered nodular cast iron evaluated by image segmentation 图像分割法评价热处理时间对等温球铁组织演变的影响

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-12-01 DOI: 10.1016/j.jalmes.2024.100135

P.A. Ramos , I.N.R. Melo , V.H.M Medeiros , P.P. Brito

This study aimed to investigate the microstructural characteristics of a pearlitic austempered nodular cast iron (ADI) prepared with different austempering times. In austempering of ductile irons, the material is austenitiezed and rapidly cooled to temperatures typically between 420 and 290°C in a salt bath to allow the formation of a microstructure composed of graphite nodules dispersed in a residual austenitic matrix, stabilized with a high carbon content, and acicular ferrite, known as “ausferrite”. Presently, microstructure characterization by optical and scanning electron microscopy were carried out after different austempering times. Neural network image segmentation using ImageJ® software was employed to perform quantitative phase analysis, and the results were compared with volume fractions obtained by XRD measurements, one of the traditional methods for determining the residual austenite content in ferrous alloys. It was found that both carbon content in austenite and austenite fraction increase with austempering time and that graphite nodule geometry becomes gradually more irregular. The proposed methodology for quantitative analysis allowed classification of microstructure constituents with high accuracy in comparison to the XRD results.

研究了不同等温时间制备的珠光体等温球墨铸铁的显微组织特征。在球墨铸铁的等温回火中，材料被奥氏体化并在盐浴中迅速冷却到420至290℃之间，以形成由分散在残余奥氏体基体中的石墨结节和针状铁素体（称为“奥氏体”）组成的微观结构。目前，采用光学显微镜和扫描电镜对不同等温时效时间的合金进行了显微组织表征。采用ImageJ®软件进行神经网络图像分割进行定量相分析，并将结果与传统的测定铁合金中残余奥氏体含量的方法之一XRD测量得到的体积分数进行比较。随着等温回火时间的延长，奥氏体中碳含量和奥氏体分数均增加，石墨球的几何形状逐渐变得不规则。与XRD结果相比，所提出的定量分析方法允许对微观结构成分进行高精度分类。

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引用次数: 0

Thermo-microstructural-mechanical modeling of the effect of wire diameters on single-bead Ti-6Al-4V wall deposits by laser wire deposition 激光线径对单头Ti-6Al-4V壁沉积影响的热显微结构-力学模拟

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-12-01 DOI: 10.1016/j.jalmes.2024.100134

Qi Zhang , Nejib Chekir , Mathieu Brochu

Six Ti-6Al-4V deposits with two geometries to extract tensile coupons from the build direction (Z) and travel direction (X), were produced by laser wire deposition (LWD) with different wire diameters. Inconsistent wall profiles were found for deposits produced with wire diameters of 1.1 and 1.6 mm due to the inhomogeneous melt pool sizes generated during the deposition process, indicating the unstable thermal history. It was found that increasing the wire diameter resulted in increased heat input, which produced coarser grains and resulted in decreased strength. Fractography analysis showed that greater amounts of defects were observed on the fracture surfaces of deposits produced with increased wire diameters, which weakened the tensile properties. The grain boundary

α

and the surrounding colony

α

facilitated crack propagation and caused early failure. This research also proposed a platform using modeling techniques to control cooling rates, microstructure (

α / β

phase fractions and

α

lath widths) and yield strength of LWD Ti-6Al-4V. The accuracy of all models was validated by comparing them with experimental data.

采用不同线径的激光线沉积（LWD）技术，制备了6种具有两种几何形状的Ti-6Al-4V镀层，分别从构建方向(Z)和行进方向(X)提取拉伸薄片。由于沉积过程中熔池尺寸的不均匀，导致线材直径为1.1和1.6 mm的镀层壁形不一致，表明其热历史不稳定。结果表明，增大线材直径导致热输入增大，晶粒变粗，强度下降。断口形貌分析表明，随着线材直径的增加，断口表面出现了更多的缺陷，从而削弱了镀层的拉伸性能。晶界α和周围的集落α有利于裂纹扩展，导致早期破坏。本研究还提出了一个利用建模技术控制Ti-6Al-4V随钻材料冷却速率、微观结构（α/β相分数和α板条宽度）和屈服强度的平台。通过与实验数据的比较，验证了各模型的准确性。

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引用次数: 0

Mechanical alloying of bronze with aluminum and nickel: Impact on corrosion resistance and hardness 青铜与铝、镍的机械合金化：对耐蚀性和硬度的影响

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-12-01 DOI: 10.1016/j.jalmes.2024.100136

Qanita Tayyaba , Adnan Qayyum Butt , Tayyab Ali khan , Zeeshan Nazar , Abdul Rehman , Wu Yusheng

The effect of alloying bronze with aluminum (Al) and nickel (Ni) on hardness and corrosion resistance is examined in this work. Bronze alloys were manufactured in vacuum induction melting (VIM) using 99.9 % pure copper as the main component. High-purity tin, aluminum, and nickel were added. This study examined the corrosion behavior of an Al and Ni-modified bronze alloy in a 3.5 % NaCl solution using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The corrosion resistance of the alloys was assessed, with findings indicating that Ni-bronze had the best corrosion resistance—nearly twice as much as bronze. Microstructural examinations and Rockwell hardness testing further revealed that nickel-bronze had the highest hardness values, owing to strong nickel intermetallic phases formed. This thorough analysis highlights how Ni-bronze alloys perform better in challenging conditions, which qualifies them for uses needing strong mechanical durability and resistance to corrosion.

研究了铝（Al）和镍（Ni）合金对青铜硬度和耐蚀性的影响。以99.9 %纯铜为主要成分，采用真空感应熔炼法制备了青铜合金。添加了高纯锡、铝和镍。采用动电位极化（PDP）和电化学阻抗谱（EIS）研究了Al和ni改性青铜合金在3.5% % NaCl溶液中的腐蚀行为。对合金的耐腐蚀性进行了评估，结果表明镍青铜的耐腐蚀性最好，几乎是青铜的两倍。显微组织检查和洛氏硬度测试进一步表明，由于形成了强镍金属间相，镍青铜的硬度值最高。这项全面的分析强调了镍青铜合金在具有挑战性的条件下表现更好，这使它们有资格用于需要强大的机械耐久性和耐腐蚀性的用途。

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引用次数: 0

Effect of hot-pressing sintering temperature and pressure on the densification and properties of Ti-TiB composites 热压烧结温度和压力对钛-钛硼复合材料致密化和性能的影响

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-11-20 DOI: 10.1016/j.jalmes.2024.100132

Padiri Murali, Kausik Chattopadhyay, Vikas Jindal

Ti/TiB composites exhibit promising potential for applications in the automotive, aerospace, and biomedical sectors. Hot pressing coupled with in situ reaction synthesis is a commonly employed technique for fabricating discontinuously TiB-reinforced titanium matrix composites. Despite its efficacy, comprehensive research investigating the influence of hot-pressing process parameters on the densification and properties of these composites remains scarce. This study systematically examined the effects of pressure (16–48 MPa) and temperature (1250 °C to 1350 °C) on the density, microstructure, and mechanical properties of Ti/TiB composites produced through hot pressing. By analyzing densification curves and rate curves, the densification behavior under varying processing conditions was elucidated. The results indicate that elevated sintering temperatures and pressures correlate with increased densification rates, reduced porosity, and enhanced sample density. A strong relationship between relative densities and hardness was observed. This research contributes to a deeper understanding of the hot-pressing sintering process for Ti-TiB composites and facilitates the optimization of processing conditions.

钛/钛硼复合材料在汽车、航空航天和生物医学领域的应用潜力巨大。热压结合原位反应合成是制造非连续 TiB 增强钛基复合材料的常用技术。尽管热压技术非常有效，但有关热压工艺参数对这些复合材料致密化和性能影响的综合研究仍然很少。本研究系统地考察了压力（16-48 兆帕）和温度（1250 ℃ 至 1350 ℃）对热压生产的钛/钛硼复合材料的密度、微观结构和机械性能的影响。通过分析致密化曲线和速率曲线，阐明了不同加工条件下的致密化行为。结果表明，烧结温度和压力的升高与致密化率的增加、孔隙率的降低和样品密度的提高相关。相对密度和硬度之间的关系也很密切。这项研究有助于加深对 Ti-TiB 复合材料热压烧结过程的理解，并有助于优化加工条件。

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引用次数: 0

Microstructural evolution and mechanical properties of Cr–Ni–Mo–V steel with banded structure during tempering 带状结构 Cr-Ni-Mo-V 钢在回火过程中的微结构演变和力学性能

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-11-20 DOI: 10.1016/j.jalmes.2024.100131

Yunfei Du , Zhengzhao Gu , Yaqin Zhang , Rui Bai

Effects of tempering temperature on the microstructure evolution and mechanical properties of Cr–Ni–Mo–V steel with banded structure were investigated in this study. It is indicated that the tempering temperature has a significant influence on the morphology of the martensite lath in the banded structure. Carbides M₃C, M₂C and M₂C/M₇C₃ are identified at tempering temperature of 430 °C, 580 °C and 630 °C, respectively. The MC precipitate is a stable phase existing in a wide range of tempering temperature. As the tempering temperature increases, the tensile strength is gradually decreased, while the elongation and impact toughness are improved. The delaminated crack observed in the fracture surface is connected to the banded structure in Cr–Ni–Mo–V steel. It is suggested that the enhancement of ductility and toughness can be attributed to the transformation of the stress state and the blunting of the crack tip. The relationship between the microstructure and mechanical properties is explored, and a detailed insight into the precipitation processes of carbides at different tempering temperature are conducted.

本研究探讨了回火温度对带状结构 Cr-Ni-Mo-V 钢微观组织演变和力学性能的影响。结果表明，回火温度对带状结构中马氏体板条的形态有显著影响。在回火温度分别为 430 ℃、580 ℃ 和 630 ℃ 时，发现了碳化物 M3C、M2C 和 M2C/M7C3。MC 沉淀是在很宽的回火温度范围内存在的稳定相。随着回火温度的升高，拉伸强度逐渐降低，而伸长率和冲击韧性却有所提高。断裂面上观察到的分层裂纹与铬-镍-钼-钒钢中的带状结构有关。这表明延展性和韧性的提高可归因于应力状态的转变和裂纹尖端的钝化。研究还探讨了微观结构与力学性能之间的关系，并对不同回火温度下碳化物的析出过程进行了深入研究。

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引用次数: 0

Data-driven design of high bulk modulus high entropy alloys using machine learning 利用机器学习以数据为驱动设计高体积模量高熵合金

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-11-15 DOI: 10.1016/j.jalmes.2024.100128

Sandeep Jain , Reliance Jain , Vinod Kumar , Sumanta Samal

In the current research, machine learning (ML) models were used as a tool for predicting the bulk modulus of High Entropy Alloys (HEAs). ML was employed to optimize HEA compositions for superior bulk modulus values. The study assessed five regression models: Random Forest (RF), K-Nearest Neighbors (KNN), XGBoost (XGB), Support Vector Regression (SVR), and Lasso regression. The XGB regression model delivered the best results, with an R-squared (R²) value of 95.2 % and an RMSE of 2.6 % on the validation dataset. The XGB model's performance was further validated by experimental work, showing an R² value of 94.8 % and an RMSE of 3.6 %. The R-squared, RMSE, and MAE values during training, testing, and validation for the XGB model ranged from 93.2 % to 99.62 %, 0.97 to 3.64, and 0.12 to 1, respectively. Furthermore, we used the top three trained models to predict the bulk modulus of six new HEAs that were not part of the training, testing, or validation datasets. These predictions achieved R² values of 94.8 %, 93.4 %, and 92.4 %, RMSE values of 3.6 %, 4.1 %, and 4.4 %, along with MAE values of 3.4 %, 3.8 %, and 4.1 %, for the XGB, Lasso, and SVR models, respectively. This work advances the field by bridging the gap in HEA discovery and property evaluation, offering novel methods for designing HEAs with desirable bulk modulus values, and unlocking new possibilities for HEA applications.

在目前的研究中，机器学习（ML）模型被用作预测高熵合金（HEAs）体积模量的工具。机器学习模型被用于优化 HEA 成分，以获得优异的体积模量值。研究评估了五个回归模型：随机森林 (RF)、K-近邻 (KNN)、XGBoost (XGB)、支持向量回归 (SVR) 和 Lasso 回归。XGB 回归模型的结果最好，在验证数据集上的 R 平方 (R2) 值为 95.2%，RMSE 为 2.6%。实验工作进一步验证了 XGB 模型的性能，其 R2 值为 94.8%，RMSE 为 3.6%。XGB 模型在训练、测试和验证过程中的 R 平方、RMSE 和 MAE 值范围分别为 93.2 % 到 99.62 %、0.97 到 3.64 以及 0.12 到 1。此外，我们还使用训练后的前三个模型来预测不属于训练、测试或验证数据集的六种新 HEA 的体积模量。XGB 模型、Lasso 模型和 SVR 模型的 R² 值分别为 94.8%、93.4% 和 92.4%，RMSE 值分别为 3.6%、4.1% 和 4.4%，MAE 值分别为 3.4%、3.8% 和 4.1%。这项研究填补了 HEA 发现和性能评估方面的空白，为设计具有理想体积模量值的 HEA 提供了新方法，并为 HEA 的应用开辟了新的可能性，从而推动了该领域的发展。

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引用次数: 0

High-temperature deformation behavior and concurrent microstructural evolution in novel Ni-based compositionally complex alloy 新型镍基成分复杂合金的高温变形行为和同步微结构演化

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-11-14 DOI: 10.1016/j.jalmes.2024.100127

Ananya Chattree , Amrit Pandey , Saurabh S. Nene , Jaiveer Singh

In this study, a novel Ni_46.8Fe₂₃Co₁₀V₇(Al, Si)_6.6 compositionally complex alloy (Ni-CCA) has been designed by merging the CALPHAD approach with the theoretical concepts (enthalpy of mixing, atomic radius mismatch parameter, valence electron concentration (VEC), and pair sigma forming elements (PSFE)). The theoretical analysis and the CALPHAD modeling predict the formation of a single FCC phase at room temperature along with the absence of TCP phases in the designed Ni-CCA. Subsequently, the pseudo-binary phase diagram obtained from Thermo-Calc through the latest HEA database predicts the presence of newer strengthening ordered phases containing Ni-Al-Si at elevated temperatures in Ni-CCA. Microstructural characterization of as-cast Ni-CCA displayed the formation of γ-FCC phase dominated microstructure containing a minor fraction of BCC phase at room temperature whereas high-temperature compression depicted synergistic precipitation of Ni-Al-Si containing L1₂ type precipitate and dynamic recovery/recrystallization events during deformation leading to a marginal drop in yield strength (YS) at 800 °C. Moreover, the formation of necklace microstructure in a deformed specimen confirms the occurrence of dynamic recrystallization (DRX) in novel Ni-CCA.

在这项研究中，通过将 CALPHAD 方法与理论概念（混合焓、原子半径失配参数、价电子浓度 (VEC) 和成对σ元素 (PSFE)）相结合，设计出了一种新型 Ni46.8Fe23Co10V7(Al,Si)6.6成分复杂合金（Ni-CCA）。理论分析和 CALPHAD 建模预测在室温下会形成单一的催化裂化相，并且在设计的 Ni-CCA 中不存在 TCP 相。随后，通过最新的 HEA 数据库从 Thermo-Calc 中获得的伪二元相图预测，在高温下，Ni-CCA 中会出现含有 Ni-Al-Si 的新型强化有序相。铸态 Ni-CCA 的微观结构特征显示，室温下形成了以γ-FCC 相为主的微观结构，其中含有少量 BCC 相，而高温压缩则显示了含有 L12 型沉淀的 Ni-Al-Si 的协同析出，以及变形过程中的动态恢复/再结晶事件，导致 800 °C 时屈服强度 (YS) 略有下降。此外，变形试样中项链状微观结构的形成证实了新型 Ni-CCA 中发生了动态再结晶 (DRX)。

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引用次数: 0

Annealing textures of low stacking fault energy (SFE) FCC materials: Traversing binary to high entropy alloys (HEAs) 低堆积断层能（SFE）催化裂化材料的退火纹理：从二元合金到高熵合金 (HEA)

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-11-14 DOI: 10.1016/j.jalmes.2024.100130

P.P. Bhattacharjee , N. Sai Teja , S. Paul , P.K. Ojha , R. Saha

Although the origin of brass-type deformation texture in low SFE alloys has been extensively investigated, the annealing textures of such materials have received less attention, mostly limited to brass and different austenitic steels. On the other hand, the annealing textures of low SFE HEAs have been investigated more intensively recently; however, a comprehensive insight into annealing texture formation from HEAs down to binary systems is missing. To bridge the gap, the annealing texture of FCC single-phase Cu-11.6 at%Al alloy with SFE ∼10

mJ m^{- 2}

comparable to HEAs was first investigated as a model binary system and compared with selected low SFE binary, medium entropy (MEAs), and HEAs to understand the similarities and characteristic differences. The cold-rolled alloy showed massive nanostructure and a typical brass-type texture featured by a strong B ({110}<112>) component expected for a low SFE alloy. Annealing resulted in ultrafine recrystallized microstructure but extensive grain growth at higher temperatures, like other binary alloys but unlike HEAs. The annealing texture showed the retention of deformation components, weak α-fiber (ND//<110>) components and a high random fraction. These features were very similar to HEAs/MEAs and attributed to the absence of oriented nucleation (ON) or oriented growth (OG) mechanisms. However, striking differences such as strong BR ({236}<385>) and D ({113}<332>) components in the brass alloy, selective growth of the G ({110}<001>) and G/B ({110}<115>) in binary Ni-60wt%Co alloy, and strong retention of the {110}<112> component in the annealing texture of (FCC+B2) dual-phase AlCrFe₂Ni₂ HEA were remarkable. These outcomes indicated underlying microstructural effects on annealing texture formation in low SFE binary to HEAs/MEAs and should motivate further research.

虽然低 SFE 合金中黄铜型变形纹理的起源已得到广泛研究，但此类材料的退火纹理却较少受到关注，主要局限于黄铜和不同的奥氏体钢。另一方面，近来对低 SFE HEA 的退火纹理进行了更深入的研究；然而，还缺少对从 HEA 到二元体系的退火纹理形成的全面了解。为了弥补这一空白，我们首先将 SFE ∼10 mJm-2 的 FCC 单相 Cu-11.6 at%Al 合金作为二元模型系统进行了退火纹理研究，并与选定的低 SFE 二元、中等熵（MEA）和 HEA 进行了比较，以了解其相似性和特征差异。冷轧合金显示出大量的纳米结构和典型的黄铜型纹理，其特点是具有低 SFE 合金应有的强 B（{110}<112>）成分。退火会导致超细再结晶微观结构，但在较高温度下会出现大量晶粒生长，这与其他二元合金相同，但与 HEA 不同。退火纹理显示了变形成分的保留、弱α纤维（ND//<110>）成分和高无规成分。这些特征与 HEAs/MEAs 非常相似，并归因于缺乏取向成核（ON）或取向生长（OG）机制。然而，黄铜合金中的 BR（{236}<385>）和 D（{113}<332>）成分很强，G（{110}<001>）和 G/B （{110}<；115>）的选择性增长，以及在（FCC+B2）双相铝铬铁镍二元 HEA 的退火纹理中{110}<112>成分的强烈保留。这些结果表明，微观结构对低 SFE 双相 HEA/MEA 的退火纹理形成有潜在影响，因此应推动进一步的研究。

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引用次数: 0

Determination the crystallographic information of hexagonal magnesium via X-ray diffraction profiles 通过 X 射线衍射曲线确定六方镁的晶体学信息

Journal of Alloys and Metallurgical Systems

Pub Date : 2024-11-13 DOI: 10.1016/j.jalmes.2024.100126

Yanlian Liu , Liyang Huang , Limin Hou , TaoTao Li

Researching the crystallographic information is imperative in hexagonal magnesium. In this paper, the comparative evaluation on the crystallite size and shape, strain and texture are carried with semi-quantitively techniques, such as Williamson-hall function, Halder-Wagner function, March-Dollase function, ellipsoid model and the Rietveld method. Both the Williamson-hall function and Williamson Hall function are suitable to determine the crystallite size and strain, while ellipsoid model is suitable to reveal the crystallite shape. With conformed by the classical texture analysis, the Rietveld method and quantitively texture is suitable to determining the texture with fiber typed texture.

研究六方镁的晶体学信息势在必行。本文采用半定量技术，如威廉姆森-霍尔函数、哈尔德-瓦格纳函数、马奇-多拉斯函数、椭球模型和里特维尔德法，对结晶尺寸和形状、应变和纹理进行了比较评价。威廉姆森-霍尔函数和威廉姆森-霍尔函数都适用于确定晶粒尺寸和应变，而椭圆体模型则适用于揭示晶粒形状。在符合经典纹理分析方法的前提下，里特维尔德法和定量纹理适用于确定纤维类型纹理。

引用次数: 0