Pub Date : 2025-02-17DOI: 10.1016/j.intermet.2025.108706
Wei Chen , Zhichao Lu , Chengzhe Wang , Xiaolong Li , Ming Yang , Guanhaojie Zheng , Yibo Zhang , Xuerui Wei , Yan Huang , Fan Zhang , Fanqiang Meng , Zhou Zhou , Dong Ma
Fe-based bulk metallic glasses (BMGs) exhibit good potential application in magnetic-electrical parts and anti-corrosion scenarios due to the good soft magnetic and mechanical properties. Despite their good properties, Fe-based BMGs generally suffer from the crystallization from a metastable glass state via structural relaxation, nucleation, and grain growth upon heating. Thus, pursuing high thermal stability is essentially the holy grail of the BMG research community. In this work, we successfully developed a series of FeCoCrMoCBTm high entropy BMGs (HE-BMGs) with superior thermal stability via microalloying and entropy tuning. Among these developed alloys, the Fe33Co15Cr17Mo13C15B6Tm2 HE-BMG exhibits the best thermal stability with crystallization temperature exceeding 900 K (916 K) and activation energy of 510.3 ± 30 kJ/mol, which is higher than most of the conventional metallic glasses (MGs). The in-situ high energy synchrotron X-ray diffraction of Fe33Co15Cr17Mo13C15B6Tm2 HE-BMG upon heating was carried out to further clarify the phase transformation mechanism and its correlation to thermal stability. This study offers some important insights into the crystallization path and thermal stability of HE-BMGs.
{"title":"In-situ study of FeCoCrMoCBTm high entropy bulk metallic glasses with high thermal stability via high-energy synchrotron X-ray diffraction","authors":"Wei Chen , Zhichao Lu , Chengzhe Wang , Xiaolong Li , Ming Yang , Guanhaojie Zheng , Yibo Zhang , Xuerui Wei , Yan Huang , Fan Zhang , Fanqiang Meng , Zhou Zhou , Dong Ma","doi":"10.1016/j.intermet.2025.108706","DOIUrl":"10.1016/j.intermet.2025.108706","url":null,"abstract":"<div><div>Fe-based bulk metallic glasses (BMGs) exhibit good potential application in magnetic-electrical parts and anti-corrosion scenarios due to the good soft magnetic and mechanical properties. Despite their good properties, Fe-based BMGs generally suffer from the crystallization from a metastable glass state via structural relaxation, nucleation, and grain growth upon heating. Thus, pursuing high thermal stability is essentially the holy grail of the BMG research community. In this work, we successfully developed a series of FeCoCrMoCBTm high entropy BMGs (HE-BMGs) with superior thermal stability via microalloying and entropy tuning. Among these developed alloys, the Fe<sub>33</sub>Co<sub>15</sub>Cr<sub>17</sub>Mo<sub>13</sub>C<sub>15</sub>B<sub>6</sub>Tm<sub>2</sub> HE-BMG exhibits the best thermal stability with crystallization temperature exceeding 900 K (916 K) and activation energy of 510.3 ± 30 kJ/mol, which is higher than most of the conventional metallic glasses (MGs). The <em>in-situ</em> high energy synchrotron X-ray diffraction of Fe<sub>33</sub>Co<sub>15</sub>Cr<sub>17</sub>Mo<sub>13</sub>C<sub>15</sub>B<sub>6</sub>Tm<sub>2</sub> HE-BMG upon heating was carried out to further clarify the phase transformation mechanism and its correlation to thermal stability. This study offers some important insights into the crystallization path and thermal stability of HE-BMGs.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108706"},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428954","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}
Pub Date : 2025-02-16DOI: 10.1016/j.intermet.2025.108707
Jian Wang , Shengde Zhang , Wei Wang , Xiaolei Wu , Fuping Yuan
Excellent synergy of yield strength and fracture toughness has been achieved in a lightweight steel by deploying heterogeneous structures and dual nanoprecipitates. Two microstructures with similar yield strength (about 1.1 GPa) have been fabricated, one is the fully recrystallized heterogeneous grain structure with higher volume fraction of nanoprecipitates (HGS1), and the other one is the heterogeneous lamella structure consisting of both un-recrystallized and recrystallized areas with lower volume fraction of nanoprecipitates (HLS). The HGS1 shows higher uniform elongation and higher fracture toughness compared to the HLS. The HGS1 displays larger size of plastic zone and higher hardening capacity around the crack tip compared to the HLS. The plastic deformation around the crack tip is accommodated by the planar dislocation slips and the formation of parallel slip bands on two {111} planes for both samples. The average interspacing of the slip bands for the HGS1 sample is found to be smaller than that for the HLS sample, indicating a stronger hardening around the crack tip for the HGS1 sample. The higher fracture toughness of the HGS1 sample can be attributed to the stronger hardening around the crack tip by the smaller spacing of planar slip bands and the stronger precipitation hardening.
{"title":"Enhanced fracture properties by heterogeneous grain structures and dual nanoprecipitates","authors":"Jian Wang , Shengde Zhang , Wei Wang , Xiaolei Wu , Fuping Yuan","doi":"10.1016/j.intermet.2025.108707","DOIUrl":"10.1016/j.intermet.2025.108707","url":null,"abstract":"<div><div>Excellent synergy of yield strength and fracture toughness has been achieved in a lightweight steel by deploying heterogeneous structures and dual nanoprecipitates. Two microstructures with similar yield strength (about 1.1 GPa) have been fabricated, one is the fully recrystallized heterogeneous grain structure with higher volume fraction of nanoprecipitates (HGS1), and the other one is the heterogeneous lamella structure consisting of both un-recrystallized and recrystallized areas with lower volume fraction of nanoprecipitates (HLS). The HGS1 shows higher uniform elongation and higher fracture toughness compared to the HLS. The HGS1 displays larger size of plastic zone and higher hardening capacity around the crack tip compared to the HLS. The plastic deformation around the crack tip is accommodated by the planar dislocation slips and the formation of parallel slip bands on two {111} planes for both samples. The average interspacing of the slip bands for the HGS1 sample is found to be smaller than that for the HLS sample, indicating a stronger hardening around the crack tip for the HGS1 sample. The higher fracture toughness of the HGS1 sample can be attributed to the stronger hardening around the crack tip by the smaller spacing of planar slip bands and the stronger precipitation hardening.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108707"},"PeriodicalIF":4.3,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420836","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}
Pub Date : 2025-02-15DOI: 10.1016/j.intermet.2025.108655
Xin Han , Chong Peng , Guangtong Zhou , Chan Han , Kenan Li , Ningchang Wang , Shuju Liang , Rui Li , Yujiao Ke
A series of oxygen-doped (Fe3Co2Ni2Cr3)94-xAlxO6 (x = 3–7 at.%) multi-principal element alloys (MPEAs) was synthesized via mechanical alloying (MA) and subsequently consolidated by high-pressure and high-temperature sintering (HPHT), and the effect of Al contents on the microstructure and hardening mechanisms was investigated systematically. Detailed microstructural characterizations indicate that (Fe3Co2Ni2Cr3)94-xAlxO6 MPEAs are composed of nanocrystalline FCC matrix, and ultrafine grained Cr-rich oxides, as well as the particle size of the Cr-rich oxides decreases and the distribution is gradually uniform with increasing Al contents. The (Fe3Co2Ni2Cr3)87Al7O6 MPEA contains small nanocrystalline Al-rich oxides. Attributed to grain boundary strengthening and strain hardening, (Fe3Co2Ni2Cr3)87Al7O6 shows a high Vickers hardness of 6.98 ± 0.16 GPa, higher than that of most previously reported FCC structured HEAs. Estimated from Tabor's equation, the Tabor's ratio attains a value of ∼2.96, consistent with that of conventional polycrystalline materials. This work provides a novel pathway for hardening MPEAs and widens the design toolbox for other high-performance materials, given the typical Tabor ratio.
{"title":"Microstructure and hardening mechanisms of oxygen-doped (Fe3Co2Ni2Cr3)94-xAlxO6 multi-principal element alloys","authors":"Xin Han , Chong Peng , Guangtong Zhou , Chan Han , Kenan Li , Ningchang Wang , Shuju Liang , Rui Li , Yujiao Ke","doi":"10.1016/j.intermet.2025.108655","DOIUrl":"10.1016/j.intermet.2025.108655","url":null,"abstract":"<div><div>A series of oxygen-doped (Fe<sub>3</sub>Co<sub>2</sub>Ni<sub>2</sub>Cr<sub>3</sub>)<sub>94-<em>x</em></sub>Al<sub><em>x</em></sub>O<sub>6</sub> (<em>x</em> = 3–7 at.%) multi-principal element alloys (MPEAs) was synthesized via mechanical alloying (MA) and subsequently consolidated by high-pressure and high-temperature sintering (HPHT), and the effect of Al contents on the microstructure and hardening mechanisms was investigated systematically. Detailed microstructural characterizations indicate that (Fe<sub>3</sub>Co<sub>2</sub>Ni<sub>2</sub>Cr<sub>3</sub>)<sub>94-<em>x</em></sub>Al<sub><em>x</em></sub>O<sub>6</sub> MPEAs are composed of nanocrystalline FCC matrix, and ultrafine grained Cr-rich oxides, as well as the particle size of the Cr-rich oxides decreases and the distribution is gradually uniform with increasing Al contents. The (Fe<sub>3</sub>Co<sub>2</sub>Ni<sub>2</sub>Cr<sub>3</sub>)<sub>87</sub>Al<sub>7</sub>O<sub>6</sub> MPEA contains small nanocrystalline Al-rich oxides. Attributed to grain boundary strengthening and strain hardening, (Fe<sub>3</sub>Co<sub>2</sub>Ni<sub>2</sub>Cr<sub>3</sub>)<sub>87</sub>Al<sub>7</sub>O<sub>6</sub> shows a high Vickers hardness of 6.98 ± 0.16 GPa, higher than that of most previously reported FCC structured HEAs. Estimated from Tabor's equation, the Tabor's ratio attains a value of ∼2.96, consistent with that of conventional polycrystalline materials. This work provides a novel pathway for hardening MPEAs and widens the design toolbox for other high-performance materials, given the typical Tabor ratio.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108655"},"PeriodicalIF":4.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420810","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}
Pub Date : 2025-02-13DOI: 10.1016/j.intermet.2025.108704
Shijiang Zhong , Mengjiao Wang , Mingfang Qian , Xinhao Wan , Xuexi Zhang , Lin Geng
In the field of magnetic refrigeration, magnetic materials that can exhibit both a giant magnetic entropy change (ΔSm) and a widened working temperature interval (δTFWHM) are being pursued. To obtain an enhanced magnetic entropy change, this study designed a magneto-structural coupled (i.e., overlapping the martensitic and magnetic transitions) Ni–Mn–Ga bulk ingot; however, it possessed a relatively narrow δTFWHM of 10 K. To broaden its δTFWHM, a microparticle with size varying from ∼38.5 to 45 μm was produced by grinding the bulk ingot and by subsequently subjecting it to stress relief annealing (SRA). Consequently, an expanded martensitic transformation width of 14 K and a broadened δTFWHM of 15 K were achieved in the SRA state. Meanwhile, the average magnetic hysteresis was reduced from 21.8 J kg−1 to 16.8 J kg−1 by preparing the alloy in the microparticle configuration. Therefore, an enhanced net refrigeration capacity value of 104.0 J kg−1 under 5 T was achieved in the SRA microparticle compared with that of 57.7 J kg−1 in the bulk ingot. The strategy of increasing the specific surface area and regulating the internal stress can be used to expand a refrigerant's δTFWHM, thereby helping achieve a higher magnetic refrigeration capacity in Ni–Mn–X alloys.
{"title":"Broadening the working temperature interval in a magneto-structural coupled Ni–Mn–Ga microparticle via introducing a free surface","authors":"Shijiang Zhong , Mengjiao Wang , Mingfang Qian , Xinhao Wan , Xuexi Zhang , Lin Geng","doi":"10.1016/j.intermet.2025.108704","DOIUrl":"10.1016/j.intermet.2025.108704","url":null,"abstract":"<div><div>In the field of magnetic refrigeration, magnetic materials that can exhibit both a giant magnetic entropy change (Δ<em>S</em><sub><em>m</em></sub>) and a widened working temperature interval (<em>δT</em><sub><em>FWHM</em></sub>) are being pursued. To obtain an enhanced magnetic entropy change, this study designed a magneto-structural coupled (i.e., overlapping the martensitic and magnetic transitions) Ni–Mn–Ga bulk ingot; however, it possessed a relatively narrow <em>δT</em><sub><em>FWHM</em></sub> of 10 K. To broaden its <em>δT</em><sub><em>FWHM</em></sub>, a microparticle with size varying from ∼38.5 to 45 μm was produced by grinding the bulk ingot and by subsequently subjecting it to stress relief annealing (SRA). Consequently, an expanded martensitic transformation width of 14 K and a broadened <em>δT</em><sub><em>FWHM</em></sub> of 15 K were achieved in the SRA state. Meanwhile, the average magnetic hysteresis was reduced from 21.8 J kg<sup>−1</sup> to 16.8 J kg<sup>−1</sup> by preparing the alloy in the microparticle configuration. Therefore, an enhanced net refrigeration capacity value of 104.0 J kg<sup>−1</sup> under 5 T was achieved in the SRA microparticle compared with that of 57.7 J kg<sup>−1</sup> in the bulk ingot. The strategy of increasing the specific surface area and regulating the internal stress can be used to expand a refrigerant's <em>δT</em><sub><em>FWHM</em></sub>, thereby helping achieve a higher magnetic refrigeration capacity in Ni–Mn–X alloys.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108704"},"PeriodicalIF":4.3,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394403","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}
Pub Date : 2025-02-12DOI: 10.1016/j.intermet.2025.108705
Tiantian Wang , Wentao Jiang , Xiaohong Wang , Bo Jiang , Xin Wang , Ye Wang , Hongyu Xu , Maoliang Hu , Dongdong Zhu
A series of novel AlNbTiV2Six (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) refractory high-entropy alloys were fabricated by vacuum arc melting. The effects of Si content on the crystal structure, microstructure and high-temperature mechanical properties of the alloys were systematically investigated, and the mechanism of properties enhancement was analyzed in depth. The results showed that the addition of Si resulted in the formation of a hexagonal close-packed M5Si3-type silicide phase (M = Al, Nb, Ti, and V), transforming the alloy from a single BCC structure to a dual-phase structure of BCC + M5Si3, and increasing the volume fraction of M5Si3 phase to 23.1 %. Furthermore, an increase in Si content is beneficial to reduce the density of the alloy. When the Si content reaches 0.5, the alloy density decreases by about 7.0 %. The results of high-temperature compression tests show that the yield strength of AlNbTiV2Six alloys has increased by nearly 70 % at 873 K, and AlNbTiV2Si0.5 alloy has the highest yield strength at 1073 K, reaching 1154 MPa. The mechanism of properties enhancement is attributed to the second phase strengthening. When the temperature continues to increase to 1273 K, the strengthening effect of silicides becomes weaker, and the yield strength of AlNbTiV2Six alloys is not significantly different, all around 200 MPa, indicating the dominant role of solid solution strengthening. In addition, the solidification path of AlNbTiV2Six alloys was analyzed and discussed. Our current work contributes to the design of new high-performance lightweight alloys with controllable structure, and provides a reference for future research, development, and production utilization.
{"title":"An investigation on high-temperature properties of a lightweight AlNbTiV2 refractory high-entropy alloy reinforced by Si","authors":"Tiantian Wang , Wentao Jiang , Xiaohong Wang , Bo Jiang , Xin Wang , Ye Wang , Hongyu Xu , Maoliang Hu , Dongdong Zhu","doi":"10.1016/j.intermet.2025.108705","DOIUrl":"10.1016/j.intermet.2025.108705","url":null,"abstract":"<div><div>A series of novel AlNbTiV<sub>2</sub>Si<sub>x</sub> (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) refractory high-entropy alloys were fabricated by vacuum arc melting. The effects of Si content on the crystal structure, microstructure and high-temperature mechanical properties of the alloys were systematically investigated, and the mechanism of properties enhancement was analyzed in depth. The results showed that the addition of Si resulted in the formation of a hexagonal close-packed M<sub>5</sub>Si<sub>3</sub>-type silicide phase (M = Al, Nb, Ti, and V), transforming the alloy from a single BCC structure to a dual-phase structure of BCC + M<sub>5</sub>Si<sub>3</sub>, and increasing the volume fraction of M<sub>5</sub>Si<sub>3</sub> phase to 23.1 %. Furthermore, an increase in Si content is beneficial to reduce the density of the alloy. When the Si content reaches 0.5, the alloy density decreases by about 7.0 %. The results of high-temperature compression tests show that the yield strength of AlNbTiV<sub>2</sub>Si<sub>x</sub> alloys has increased by nearly 70 % at 873 K, and AlNbTiV<sub>2</sub>Si<sub>0.5</sub> alloy has the highest yield strength at 1073 K, reaching 1154 MPa. The mechanism of properties enhancement is attributed to the second phase strengthening. When the temperature continues to increase to 1273 K, the strengthening effect of silicides becomes weaker, and the yield strength of AlNbTiV<sub>2</sub>Si<sub>x</sub> alloys is not significantly different, all around 200 MPa, indicating the dominant role of solid solution strengthening. In addition, the solidification path of AlNbTiV<sub>2</sub>Si<sub>x</sub> alloys was analyzed and discussed. Our current work contributes to the design of new high-performance lightweight alloys with controllable structure, and provides a reference for future research, development, and production utilization.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108705"},"PeriodicalIF":4.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394404","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}
Pub Date : 2025-02-12DOI: 10.1016/j.intermet.2025.108703
Z.B. Song , T.X. Huang , Aditya Jain , Y.G. Wang
High-entropy alloys have attracted considerable attention due to their advantages such as versatility and customizable properties. The customizable properties in soft magnetic high-entropy alloys mainly come from non-ferromagnetic elements, but it is challenging to maintain good soft magnetic properties while increasing the proportion of non-ferromagnetic elements. In this study, the ratio of non-ferromagnetic elements is systematically adjusted in the FeCoMnAlSi high-entropy alloy to explore its influence on soft magnetic properties. The structure of the alloys transforms in a sequence of FCC + BCC → BCC → BCC + B2 as the proportion of non-ferromagnetic elements increases. The soft magnetic properties of the system are significantly influenced by non-ferromagnetic elements. The dependence of saturation magnetization (Ms) on the proportion of non-ferromagnetic elements exhibits an И-shaped pattern, while that of coercivity (Hc) follows a V-shaped trend. Notably, the alloy (Fe4/5Co1/5)78(Mn10/23Al10/23Si3/23)22 exhibits an exceptionally high Ms of 189.12 emu·g−1 and a low Hc of 1.9 Oe. Simulation calculations indicated that the enhancement in Ms results from a reduction in the antiferromagnetic coupling between Fe and Mn, coupled with an improved efficiency of the ferromagnetic transformation in Mn.
{"title":"Effect of non-ferromagnetic element content on magnetic properties of FeCoMnAlSi high entropy alloy","authors":"Z.B. Song , T.X. Huang , Aditya Jain , Y.G. Wang","doi":"10.1016/j.intermet.2025.108703","DOIUrl":"10.1016/j.intermet.2025.108703","url":null,"abstract":"<div><div>High-entropy alloys have attracted considerable attention due to their advantages such as versatility and customizable properties. The customizable properties in soft magnetic high-entropy alloys mainly come from non-ferromagnetic elements, but it is challenging to maintain good soft magnetic properties while increasing the proportion of non-ferromagnetic elements. In this study, the ratio of non-ferromagnetic elements is systematically adjusted in the FeCoMnAlSi high-entropy alloy to explore its influence on soft magnetic properties. The structure of the alloys transforms in a sequence of FCC + BCC → BCC → BCC + B2 as the proportion of non-ferromagnetic elements increases. The soft magnetic properties of the system are significantly influenced by non-ferromagnetic elements. The dependence of saturation magnetization (<em>M</em><sub>s</sub>) on the proportion of non-ferromagnetic elements exhibits an И-shaped pattern, while that of coercivity (<em>H</em><sub>c</sub>) follows a V-shaped trend. Notably, the alloy (Fe<sub>4/5</sub>Co<sub>1/5</sub>)<sub>78</sub>(Mn<sub>10/23</sub>Al<sub>10/23</sub>Si<sub>3/23</sub>)<sub>22</sub> exhibits an exceptionally high <em>M</em><sub>s</sub> of 189.12 emu·g<sup>−1</sup> and a low <em>H</em><sub>c</sub> of 1.9 Oe. Simulation calculations indicated that the enhancement in <em>M</em><sub>s</sub> results from a reduction in the antiferromagnetic coupling between Fe and Mn, coupled with an improved efficiency of the ferromagnetic transformation in Mn.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108703"},"PeriodicalIF":4.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388129","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}
In this study, various heat treatment processes were employed to adjust the ratio of blocky γ phase to α2/γ lamellae and to create conditions conducive to the precipitation of Y2O3 nanoparticles. The aim was to investigate the influence of microstructure evolution on the high-temperature mechanical properties and creep behavior of the Ti-48Al-2Cr-2Nb-0.05Y2O3 alloy. As the holding temperature increases from 1200 °C to 1350 °C, the content of the blocky γ phase decreases from 61.49 % to 1.12 %, resulting in the formation of nearly duplex (NDP) microstructure, duplex (DP) microstructure, nearly lamellar (NL) microstructure, and fully lamellar (FL) microstructure. The combination of elevated temperature conditions and increased crystal defects promotes the precipitation of Y2O3 nanoparticles, leading to the highest number of nanoscale reinforcements within the FL microstructure. As the heat-treated sample transitions from the NDP to FL microstructure, the ultimate tensile strength tested at 800 °C increases from 384 MPa to 668 MPa, while the creep life tested at 800 °C under 325 MPa improves from 10.8 h to 138.2 h. The elongation and creep strain initially increase and then decrease, with the heat-treated sample exhibiting an NL microstructure demonstrating the best high-temperature elongation of 21.48 % and the highest creep strain of 19.55 %. The favorable ductility and deformation capacity observed in the NL microstructure can be attributed to the cooperative deformation of the lamellar structure and its surrounding blocky γ phase. The excellent high-temperature strength and creep resistance of the FL microstructure result from the synergistic strengthening effect arising from a greater number of nanoscale Y2O3 precipitates and the highest content of lamellar colonies, which provide an effective pinning effect on dislocation movement. In comparison to commonly used reinforcements, the heat-treated TiAl alloys reinforced with dual-scale Y2O3 particles exhibit remarkable high-temperature properties, which are anticipated to further enhance the service temperature of TiAl alloys and expand their application at elevated temperatures.
{"title":"The effect of microstructure evolution on the high-temperature mechanical properties and creep behavior of Y2O3-bearing alloy","authors":"Yingfei Guo , Wenjing Liang , Jiayan Zhou , Shulong Xiao , Lijuan Xu , Yu Liang , Yuyong Chen","doi":"10.1016/j.intermet.2025.108702","DOIUrl":"10.1016/j.intermet.2025.108702","url":null,"abstract":"<div><div>In this study, various heat treatment processes were employed to adjust the ratio of blocky γ phase to α<sub>2</sub>/γ lamellae and to create conditions conducive to the precipitation of Y<sub>2</sub>O<sub>3</sub> nanoparticles. The aim was to investigate the influence of microstructure evolution on the high-temperature mechanical properties and creep behavior of the Ti-48Al-2Cr-2Nb-0.05Y<sub>2</sub>O<sub>3</sub> alloy. As the holding temperature increases from 1200 °C to 1350 °C, the content of the blocky γ phase decreases from 61.49 % to 1.12 %, resulting in the formation of nearly duplex (NDP) microstructure, duplex (DP) microstructure, nearly lamellar (NL) microstructure, and fully lamellar (FL) microstructure. The combination of elevated temperature conditions and increased crystal defects promotes the precipitation of Y<sub>2</sub>O<sub>3</sub> nanoparticles, leading to the highest number of nanoscale reinforcements within the FL microstructure. As the heat-treated sample transitions from the NDP to FL microstructure, the ultimate tensile strength tested at 800 °C increases from 384 MPa to 668 MPa, while the creep life tested at 800 °C under 325 MPa improves from 10.8 h to 138.2 h. The elongation and creep strain initially increase and then decrease, with the heat-treated sample exhibiting an NL microstructure demonstrating the best high-temperature elongation of 21.48 % and the highest creep strain of 19.55 %. The favorable ductility and deformation capacity observed in the NL microstructure can be attributed to the cooperative deformation of the lamellar structure and its surrounding blocky γ phase. The excellent high-temperature strength and creep resistance of the FL microstructure result from the synergistic strengthening effect arising from a greater number of nanoscale Y<sub>2</sub>O<sub>3</sub> precipitates and the highest content of lamellar colonies, which provide an effective pinning effect on dislocation movement. In comparison to commonly used reinforcements, the heat-treated TiAl alloys reinforced with dual-scale Y<sub>2</sub>O<sub>3</sub> particles exhibit remarkable high-temperature properties, which are anticipated to further enhance the service temperature of TiAl alloys and expand their application at elevated temperatures.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108702"},"PeriodicalIF":4.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388130","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}
Pub Date : 2025-02-11DOI: 10.1016/j.intermet.2025.108690
Congqi Fu , Bowen Zhang , Xiaona Zhang , Lin Ge , Yumo Wen , Hui Li , Tao Yu , Chongyu Wang , Ze Zhang
The strain field near the γ/γ′ interface has a significant influence on the morphology evolution and the mechanical properties of Ni-based single crystal superalloys. The present work precisely determines the strain field near the γ/γ′ interface in a Ni-Al binary model single crystal superalloy by a combined usage of convergent beam electron diffraction (CBED) and high-resolution transmission electron microscopy (HRTEM) method. At positions slightly away from the γ/γ′ interface, the variation of lattice is sensitively measured by using standard CBED method. Within the range of about 10 nm close to the γ/γ′ interface, which is difficult to obtain a clear HOLZ pattern through traditional CBED solely, by using the CBED-calibrated HRTEM results, the complete lattice distortion and strain field are obtained. There is compressive strain in the γ′ phase and tensile strain in the γ phase, and the lattice strain affects a range as long as 80 nm near γ/γ′ interface. The strain distribution in the two phases is asymmetric, with the strain field in the γ phase obviously larger than in the γ′ phase. Our results provide important fundamental data for understands on the relationship between microstructure evolution and properties of Ni-based single crystal superalloys.
{"title":"The strain field near the γ/γ′ interface in Ni-Al binary model single crystal superalloy","authors":"Congqi Fu , Bowen Zhang , Xiaona Zhang , Lin Ge , Yumo Wen , Hui Li , Tao Yu , Chongyu Wang , Ze Zhang","doi":"10.1016/j.intermet.2025.108690","DOIUrl":"10.1016/j.intermet.2025.108690","url":null,"abstract":"<div><div>The strain field near the γ/γ′ interface has a significant influence on the morphology evolution and the mechanical properties of Ni-based single crystal superalloys. The present work precisely determines the strain field near the γ/γ′ interface in a Ni-Al binary model single crystal superalloy by a combined usage of convergent beam electron diffraction (CBED) and high-resolution transmission electron microscopy (HRTEM) method. At positions slightly away from the γ/γ′ interface, the variation of lattice is sensitively measured by using standard CBED method. Within the range of about 10 nm close to the γ/γ′ interface, which is difficult to obtain a clear HOLZ pattern through traditional CBED solely, by using the CBED-calibrated HRTEM results, the complete lattice distortion and strain field are obtained. There is compressive strain in the γ′ phase and tensile strain in the γ phase, and the lattice strain affects a range as long as 80 nm near γ/γ′ interface. The strain distribution in the two phases is asymmetric, with the strain field in the γ phase obviously larger than in the γ′ phase. Our results provide important fundamental data for understands on the relationship between microstructure evolution and properties of Ni-based single crystal superalloys.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108690"},"PeriodicalIF":4.3,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388128","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}
The thermal memory effect, TME, has been studied in Ni55Fe19Ga26 shape memory alloys, fabricated as ribbons via melt-spinning and as pellets via arc-melting, to evaluate its dependence on the martensitic structure and the macrostructure of the samples. When the reverse martensitic transformation is interrupted, a kinetic delay in the subsequent complete transformation is only evident in the ribbon samples, where the 14M modulated structure is the dominant phase. In contrast, degradation of the modulated structure or the presence of the phase significantly reduces the observed TME. In such cases, the magnitude of the TME approaches the detection limits of commercial calorimeters, and only high-resolution calorimeter at very low heating rate (40 mK h−1) can show the effect. Following the kinetic arrest and subsequent cooling, the reverse martensitic transformation was completed at several heating rates to confirm the athermal nature of the phenomenon.
{"title":"Phase dependence of the thermal memory effect in polycrystalline ribbon and bulk Ni55Fe19Ga26 Heusler alloys","authors":"A. Vidal-Crespo , A.F. Manchón-Gordón , J.M. Martín-Olalla , F.J. Romero , J.J. Ipus , M.C. Gallardo , J.S. Blázquez , C.F. Conde","doi":"10.1016/j.intermet.2025.108695","DOIUrl":"10.1016/j.intermet.2025.108695","url":null,"abstract":"<div><div>The thermal memory effect, TME, has been studied in Ni<sub>55</sub>Fe<sub>19</sub>Ga<sub>26</sub> shape memory alloys, fabricated as ribbons via melt-spinning and as pellets via arc-melting, to evaluate its dependence on the martensitic structure and the macrostructure of the samples. When the reverse martensitic transformation is interrupted, a kinetic delay in the subsequent complete transformation is only evident in the ribbon samples, where the 14M modulated structure is the dominant phase. In contrast, degradation of the modulated structure or the presence of the <span><math><mrow><mi>γ</mi></mrow></math></span> phase significantly reduces the observed TME. In such cases, the magnitude of the TME approaches the detection limits of commercial calorimeters, and only high-resolution calorimeter at very low heating rate (40 mK h<sup>−1</sup>) can show the effect. Following the kinetic arrest and subsequent cooling, the reverse martensitic transformation was completed at several heating rates to confirm the athermal nature of the phenomenon.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108695"},"PeriodicalIF":4.3,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143373076","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}
Pub Date : 2025-02-05DOI: 10.1016/j.intermet.2025.108693
Dexiao Dong , Guoqiang Liu , Weimin Guo , Yu Zhang , Ning Ding , Long Liu , Na Xu , Lizong Chen , Yelong An , Yakai Bai
This study details the synthesis of an AlCoCrFeNi2.1 high entropy alloy via laser cladding. The specimens are treated by heating them to 800 °C, 1000 °C, 1200 °C, and 1300 °C, respectively, holding them for an hour, and then cooling them in water. The purpose of the study is to explore the effect of high temperature heat treatment on the microstructural evolution and mechanical properties of the alloy. FCC + BCC dual phase microstructure was present in the samples before and after heat treatment. The microstructure was refined first, and then coarsened, as the temperature rose from 800 °C to 1300 °C. New BCC phase appeared in the initial FCC grains after treated at 800 °C, 1000 °C, and 1200 °C, and no new BCC phase was found in the coating heat treated at 1300 °C. Differences in the diffusion rates of Al, Co, Cr, Fe, and Ni atoms at elevated temperatures leads to an increase in size of the newly precipitated phases. The precipitation of BCC phase during high-temperature heat treatment is promoted by the significant negative mixing enthalpy between Al and Ni. At the optimal heat treatment temperature of 800 °C and 1000 °C, respectively, the sample exhibits optimal hardness and wear resistance. Its corrosion performance is also optimized at this temperature. Fatigue wear, bonding wear, oxidation wear, and abrasive wear are the wear mechanisms of as deposited and heat-treated samples. BCC phase, which is rich in Al & Ni, shows lower corrosion resistance and is preferentially corroded.
{"title":"The effect of heat-treatment on microstructure, wear resistance, and corrosion resistance of laser cladding AlCoCrFeNi2.1 high entropy alloy coating","authors":"Dexiao Dong , Guoqiang Liu , Weimin Guo , Yu Zhang , Ning Ding , Long Liu , Na Xu , Lizong Chen , Yelong An , Yakai Bai","doi":"10.1016/j.intermet.2025.108693","DOIUrl":"10.1016/j.intermet.2025.108693","url":null,"abstract":"<div><div>This study details the synthesis of an AlCoCrFeNi<sub>2.1</sub> high entropy alloy via laser cladding. The specimens are treated by heating them to 800 °C, 1000 °C, 1200 °C, and 1300 °C, respectively, holding them for an hour, and then cooling them in water. The purpose of the study is to explore the effect of high temperature heat treatment on the microstructural evolution and mechanical properties of the alloy. FCC + BCC dual phase microstructure was present in the samples before and after heat treatment. The microstructure was refined first, and then coarsened, as the temperature rose from 800 °C to 1300 °C. New BCC phase appeared in the initial FCC grains after treated at 800 °C, 1000 °C, and 1200 °C, and no new BCC phase was found in the coating heat treated at 1300 °C. Differences in the diffusion rates of Al, Co, Cr, Fe, and Ni atoms at elevated temperatures leads to an increase in size of the newly precipitated phases. The precipitation of BCC phase during high-temperature heat treatment is promoted by the significant negative mixing enthalpy between Al and Ni. At the optimal heat treatment temperature of 800 °C and 1000 °C, respectively, the sample exhibits optimal hardness and wear resistance. Its corrosion performance is also optimized at this temperature. Fatigue wear, bonding wear, oxidation wear, and abrasive wear are the wear mechanisms of as deposited and heat-treated samples. BCC phase, which is rich in Al & Ni, shows lower corrosion resistance and is preferentially corroded.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"180 ","pages":"Article 108693"},"PeriodicalIF":4.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143329882","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}
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