Pub Date : 2025-11-01DOI: 10.1016/S1003-6326(25)66900-7
Shu-hui LIU , Qing-lin PAN , Hong-feng HUANG , Jing WANG , De-gui LI , Zhi-xin NING , Li-li WEI
The microstructure evolution and strengthening ability of natural aging (NA), delayed aging (DA), and DA after pre-aging (PDA) of Al-Mg-Si alloy were studied. Results show that small and unstable atomic clusters are generated during NA, leading to the formation of low-density coarse βʺ and β′ phases, thus reducing the strength of DA alloy. However, atomic clusters and GP zones with larger sizes and high Mg/Si molar ratio form during pre-aging treatment. They prevent the generation of clusters during NA and can serve as effective nucleation sites in subsequent artificial aging, which elevates the number density of fine βʺ precipitates and improves the alloy strength. After pre-aging at 175 °C, the strengthening capacity of PDA alloy is restored, with hardness and yield strength reaching 95.1% and 101.9% of peak-aged alloy.
{"title":"Effect of natural aging and pre-aging on microstructure evolution and strengthening ability of Al-Mg-Si alloy during age hardening","authors":"Shu-hui LIU , Qing-lin PAN , Hong-feng HUANG , Jing WANG , De-gui LI , Zhi-xin NING , Li-li WEI","doi":"10.1016/S1003-6326(25)66900-7","DOIUrl":"10.1016/S1003-6326(25)66900-7","url":null,"abstract":"<div><div>The microstructure evolution and strengthening ability of natural aging (NA), delayed aging (DA), and DA after pre-aging (PDA) of Al-Mg-Si alloy were studied. Results show that small and unstable atomic clusters are generated during NA, leading to the formation of low-density coarse βʺ and β′ phases, thus reducing the strength of DA alloy. However, atomic clusters and GP zones with larger sizes and high Mg/Si molar ratio form during pre-aging treatment. They prevent the generation of clusters during NA and can serve as effective nucleation sites in subsequent artificial aging, which elevates the number density of fine βʺ precipitates and improves the alloy strength. After pre-aging at 175 °C, the strengthening capacity of PDA alloy is restored, with hardness and yield strength reaching 95.1% and 101.9% of peak-aged alloy.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3578-3594"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66904-4
Fang YU , Ling-fei YANG , Zhong-chao ZHAO , Xiang-jie WANG , Cheng-cheng CHEN , Jian-zhong CUI
The effects of the inter-annealing process on the microstructure, plane stress fracture toughness, and tensile properties of an AA7075 cladding sheet were investigated using optical microscopy, scanning electron microscopy, electron backscattered diffraction, transmission electron microscopy, and mechanical property tests. The results indicate that the plane stress fracture toughness of AA7075-T6 cladding sheet can be greatly improved. The plane stress fracture toughness for the longitudinal-transverse (L-T) and transverse-longitudinal (T-L) directions were 117.7 and 94.8 MPa·m1/2, respectively, after intermediate annealing at 380 °C. This represents an increase of 23.9 MPa·m1/2 in the L-T direction and 22.6 MPa·m1/2 in the T-L direction compared with the AA7075-T6 cladding sheet without intermediate annealing. Moreover, the tensile strength remains similar under different conditions. Microstructure analysis indicates that intermediate annealing before heat treatment can result in long sub-grains, few recrystallized grain boundaries, and small size precipitates in AA7075-T6 cladding sheets.
{"title":"Effect of annealing process on microstructure and plane stress fracture toughness of 7075 cladding sheet","authors":"Fang YU , Ling-fei YANG , Zhong-chao ZHAO , Xiang-jie WANG , Cheng-cheng CHEN , Jian-zhong CUI","doi":"10.1016/S1003-6326(25)66904-4","DOIUrl":"10.1016/S1003-6326(25)66904-4","url":null,"abstract":"<div><div>The effects of the inter-annealing process on the microstructure, plane stress fracture toughness, and tensile properties of an AA7075 cladding sheet were investigated using optical microscopy, scanning electron microscopy, electron backscattered diffraction, transmission electron microscopy, and mechanical property tests. The results indicate that the plane stress fracture toughness of AA7075-T6 cladding sheet can be greatly improved. The plane stress fracture toughness for the longitudinal-transverse (L-T) and transverse-longitudinal (T-L) directions were 117.7 and 94.8 MPa·m<sup>1/2</sup>, respectively, after intermediate annealing at 380 °C. This represents an increase of 23.9 MPa·m<sup>1/2</sup> in the L-T direction and 22.6 MPa·m<sup>1/2</sup> in the T-L direction compared with the AA7075-T6 cladding sheet without intermediate annealing. Moreover, the tensile strength remains similar under different conditions. Microstructure analysis indicates that intermediate annealing before heat treatment can result in long sub-grains, few recrystallized grain boundaries, and small size precipitates in AA7075-T6 cladding sheets.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3650-3661"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66910-X
Wen-qi LIU , Shuai WANG , Xin CHEN , Lu-jun HUANG , Jia-yi JIN , Feng-bo SUN , Wei-hang LU , Lin GENG
In order to achieve the strength-ductility synergy and improve the work-hardening capacity, Ti64 based composites with dispersive nanoscaled TiB whiskers inside grains were fabricated by plasma rotating electrode process coupled with spark plasma sintering. Based on the rapid eutectic reaction, the nanoscaled TiB whiskers exhibited ultra-fine network distribution in composite powders. During the spark plasma sintering process, the network dissolved, and TiB followed the Ostwald ripening mechanism and merged along the (100) plane. The intragranular TiB whiskers could significantly refine the primary β grain and α lath. The ultimate tensile strength of the composite with only 2 vol.% TiB whiskers was enhanced to (1123±17) MPa while the elongation was similar to that of the as-sintered Ti64 alloy with approximately 8%. The strength-ductility synergy effect was mainly attributed to the significant grain refinement and the work-hardening ability improvement contributed by intragranular nanoscaled TiB.
{"title":"Dispersion of nano-TiB in Ti64 based composite through plasma rotating electrode process followed by spark plasma sintering","authors":"Wen-qi LIU , Shuai WANG , Xin CHEN , Lu-jun HUANG , Jia-yi JIN , Feng-bo SUN , Wei-hang LU , Lin GENG","doi":"10.1016/S1003-6326(25)66910-X","DOIUrl":"10.1016/S1003-6326(25)66910-X","url":null,"abstract":"<div><div>In order to achieve the strength-ductility synergy and improve the work-hardening capacity, Ti64 based composites with dispersive nanoscaled TiB whiskers inside grains were fabricated by plasma rotating electrode process coupled with spark plasma sintering. Based on the rapid eutectic reaction, the nanoscaled TiB whiskers exhibited ultra-fine network distribution in composite powders. During the spark plasma sintering process, the network dissolved, and TiB followed the Ostwald ripening mechanism and merged along the (100) plane. The intragranular TiB whiskers could significantly refine the primary β grain and α lath. The ultimate tensile strength of the composite with only 2 vol.% TiB whiskers was enhanced to (1123±17) MPa while the elongation was similar to that of the as-sintered Ti64 alloy with approximately 8%. The strength-ductility synergy effect was mainly attributed to the significant grain refinement and the work-hardening ability improvement contributed by intragranular nanoscaled TiB.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3751-3760"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66912-3
Pei-zhi YAN , Dong-xu WEN , Qi-feng DING , Liang HUANG , Xiao-li YANG , Zhi-cheng ZHANG , Jian-jun LI
The high-temperature deformation and dynamic recrystallization (DRX) behaviors of GH4698 superalloy were investigated via hot compression tests, and an improved unified dislocation density-based constitutive model was established. The results indicate that with the temperature decreasing or the strain rate increasing, the flow stress increases and the DRX fraction decreases. However, as the strain rate increases from 1 to 10 s-1, rapid dislocation multiplication and deformation heat accelerate the DRX nucleation, which further increases the DRX fraction. Discontinuous DRX nucleation is the dominant DRX nucleation mechanism, and continuous DRX nucleation mainly occurs under low strain rates. For the developed improved unified dislocation density-based constitutive model, the correlation coefficient, average absolute relative error, and root mean square error between the measured and predicted stresses are 0.994, 7.32% and 10.8 MPa, respectively. Meanwhile, the correlation coefficient between the measured and predicted DRX fractions is 0.976. These indicate that the developed model exhibits high accuracy in predicting the high-temperature deformation and DRX behaviors of GH4698 superalloy.
{"title":"Improved unified dislocation density-based constitutive model for high-temperature deformation and dynamic recrystallization behaviors of GH4698 superalloy","authors":"Pei-zhi YAN , Dong-xu WEN , Qi-feng DING , Liang HUANG , Xiao-li YANG , Zhi-cheng ZHANG , Jian-jun LI","doi":"10.1016/S1003-6326(25)66912-3","DOIUrl":"10.1016/S1003-6326(25)66912-3","url":null,"abstract":"<div><div>The high-temperature deformation and dynamic recrystallization (DRX) behaviors of GH4698 superalloy were investigated via hot compression tests, and an improved unified dislocation density-based constitutive model was established. The results indicate that with the temperature decreasing or the strain rate increasing, the flow stress increases and the DRX fraction decreases. However, as the strain rate increases from 1 to 10 s<sup>-1</sup>, rapid dislocation multiplication and deformation heat accelerate the DRX nucleation, which further increases the DRX fraction. Discontinuous DRX nucleation is the dominant DRX nucleation mechanism, and continuous DRX nucleation mainly occurs under low strain rates. For the developed improved unified dislocation density-based constitutive model, the correlation coefficient, average absolute relative error, and root mean square error between the measured and predicted stresses are 0.994, 7.32% and 10.8 MPa, respectively. Meanwhile, the correlation coefficient between the measured and predicted DRX fractions is 0.976. These indicate that the developed model exhibits high accuracy in predicting the high-temperature deformation and DRX behaviors of GH4698 superalloy.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3778-3794"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66918-4
Zheng-qi GUO , Xing CHEN , Yue SHI , De-qing ZHU , Jian PAN , Cong-cong YANG , Si-wei LI , Ji-wei XU , Xin WANG
The melting and separation behavior of vanadium-titanium magnetite pellets directed at an efficient extraction of vanadium and titanium was systematically investigated. Applying FactSage simulations and experiments, the smelting separation of three pre-reduced pellets from different regions was analyzed. The simulations demonstrate that FeTi2O5 is converted to TiC at low temperatures, necessitating suppression of this step. Experiments under optimized conditions (1590-1690 °C, 20-25 min, 2% coke, basicity 0.4-0.6, and 3.0%-6.0% MgO) yield iron grade of 92.35%- 95.06%, titanium grade of 34.37%-39.89%, and vanadium grade of 0.56%-1.52%, with recoveries of 99.52%-99.60%, 94.08%-98.96%, and 92.63%-94.38% for iron, titanium and vanadium, respectively. The titanium in the slag, primarily in the form of anosovite, is suitable for sulfuric acid-based titanium white production. An increase in basicity, MgO content, and pellet metallization serves to improve vanadium recovery in melted iron but lowers the titanium grade in the slag. The overall process effectively utilizes vanadium and titanium resources under optimized conditions.
{"title":"Smelting separation behaviors of various reduced vanadium titanomagnetite pellets","authors":"Zheng-qi GUO , Xing CHEN , Yue SHI , De-qing ZHU , Jian PAN , Cong-cong YANG , Si-wei LI , Ji-wei XU , Xin WANG","doi":"10.1016/S1003-6326(25)66918-4","DOIUrl":"10.1016/S1003-6326(25)66918-4","url":null,"abstract":"<div><div>The melting and separation behavior of vanadium-titanium magnetite pellets directed at an efficient extraction of vanadium and titanium was systematically investigated. Applying FactSage simulations and experiments, the smelting separation of three pre-reduced pellets from different regions was analyzed. The simulations demonstrate that FeTi<sub>2</sub>O<sub>5</sub> is converted to TiC at low temperatures, necessitating suppression of this step. Experiments under optimized conditions (1590-1690 °C, 20-25 min, 2% coke, basicity 0.4-0.6, and 3.0%-6.0% MgO) yield iron grade of 92.35%- 95.06%, titanium grade of 34.37%-39.89%, and vanadium grade of 0.56%-1.52%, with recoveries of 99.52%-99.60%, 94.08%-98.96%, and 92.63%-94.38% for iron, titanium and vanadium, respectively. The titanium in the slag, primarily in the form of anosovite, is suitable for sulfuric acid-based titanium white production. An increase in basicity, MgO content, and pellet metallization serves to improve vanadium recovery in melted iron but lowers the titanium grade in the slag. The overall process effectively utilizes vanadium and titanium resources under optimized conditions.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3869-3885"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66906-8
Wen-long XU , Xian-hua CHEN , Lu DENG , Guan-zheng ZHU , Yuan YUAN , Fu-sheng PAN
The impact of Y content on the microstructure, mechanical properties, and electromagnetic interference shielding effectiveness (EMI SE) of the Mg-6Zn-xY-1La-0.5Zr alloy was investigated. After the extrusion treatment of Mg-6Zn-xY-1La-0.5Zr alloy, the large grains that did not experience dynamic recrystallization were elongated along the extrusion direction, and the small-sized dynamic recrystallized grains were distributed around the large grains. The Mg-6Zn-1Y-1La-0.5Zr alloy demonstrated a favorable balance between strength and plasticity, exhibiting ultimate tensile strength, yield strength, and elongation values of 332.3 MPa, 267.3 MPa, and 16.2%, respectively. Moreover, the EMI SE within the frequency range of 30-1500 MHz changes from 79 to 110 dB, aligning with the electromagnetic shielding requirements of many high-strength applications.
{"title":"Effect of Y content on mechanical properties and electromagnetic interference shielding effectiveness of Mg-6Zn-xY-1La-0.5Zr alloy","authors":"Wen-long XU , Xian-hua CHEN , Lu DENG , Guan-zheng ZHU , Yuan YUAN , Fu-sheng PAN","doi":"10.1016/S1003-6326(25)66906-8","DOIUrl":"10.1016/S1003-6326(25)66906-8","url":null,"abstract":"<div><div>The impact of Y content on the microstructure, mechanical properties, and electromagnetic interference shielding effectiveness (EMI SE) of the Mg-6Zn-xY-1La-0.5Zr alloy was investigated. After the extrusion treatment of Mg-6Zn-xY-1La-0.5Zr alloy, the large grains that did not experience dynamic recrystallization were elongated along the extrusion direction, and the small-sized dynamic recrystallized grains were distributed around the large grains. The Mg-6Zn-1Y-1La-0.5Zr alloy demonstrated a favorable balance between strength and plasticity, exhibiting ultimate tensile strength, yield strength, and elongation values of 332.3 MPa, 267.3 MPa, and 16.2%, respectively. Moreover, the EMI SE within the frequency range of 30-1500 MHz changes from 79 to 110 dB, aligning with the electromagnetic shielding requirements of many high-strength applications.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3677-3696"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66903-2
Guo-fu XU , Jing-yun FU , Hao-ran LI , Meng-jiao LIU , Xiao-yan PENG , Lei TANG , Yao LI
The intergranular corrosion behavior of 2050 Al-Li alloy subjected to non-isothermal aging (NIA) treatment with varying pre-deformation amounts was investigated. Results indicate that the resistance to intergranular corrosion improves with increasing pre-deformation amouts. However, when the pre-deformation amount reaches 20%, the corrosion resistance deteriorates. Microstructural analyses via transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) reveal that as pre-deformation amount increases, the fraction of high-angle grain boundaries (HAGBs) decreases, while the proportion of low-angle grain boundaries (LAGBs) increases. This change provides additional nucleation sites for precipitates, leading to a reduction in T1 phase size and an increase in T1 phase density. The finer T1 phases contribute to a lower localized potential difference within the grains, slowering corrosion propagation. Furthermore, during corrosion, preferential dissolution of Li results in Cu enrichment along grain boundaries, which further reduces the intergranular corrosion resistance.
{"title":"Effect of pre-deformation on microstructure and intergranular corrosion behavior of 2050 Al-Li alloy","authors":"Guo-fu XU , Jing-yun FU , Hao-ran LI , Meng-jiao LIU , Xiao-yan PENG , Lei TANG , Yao LI","doi":"10.1016/S1003-6326(25)66903-2","DOIUrl":"10.1016/S1003-6326(25)66903-2","url":null,"abstract":"<div><div>The intergranular corrosion behavior of 2050 Al-Li alloy subjected to non-isothermal aging (NIA) treatment with varying pre-deformation amounts was investigated. Results indicate that the resistance to intergranular corrosion improves with increasing pre-deformation amouts. However, when the pre-deformation amount reaches 20%, the corrosion resistance deteriorates. Microstructural analyses via transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) reveal that as pre-deformation amount increases, the fraction of high-angle grain boundaries (HAGBs) decreases, while the proportion of low-angle grain boundaries (LAGBs) increases. This change provides additional nucleation sites for precipitates, leading to a reduction in T<sub>1</sub> phase size and an increase in T<sub>1</sub> phase density. The finer T<sub>1</sub> phases contribute to a lower localized potential difference within the grains, slowering corrosion propagation. Furthermore, during corrosion, preferential dissolution of Li results in Cu enrichment along grain boundaries, which further reduces the intergranular corrosion resistance.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3638-3649"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-01DOI: 10.1016/S1003-6326(25)66905-6
Si-zhe NIU , Ze-long WANG , Zi-xuan CHEN , Ran ZONG , Bao-tao CHI , Jun WANG , Shi-ying LIU , Yun-wu MA , Shan-qing HU
TIG surface remelting was performed to strengthen the surface of ZL109G alloy piston. The macrostructure indicates that surface remelting leads to the production of a remelted zone (RZ). The diameter of the primary Si decreases from 65.8 μm in the base metal (BM) to 7.1 μm in RZ. The grain size of the RZ is refined to be approximately one-seventh that of the BM. The cellular microstructure in the RZ is characterised by the α(Al) in the centre and intermetallics preferentially located at the cellular boundaries. The results of the mechanical properties demonstrate that the average hardness value of RZ increases by 39% compared to that of BM. For the transverse samples, the ultimate tensile strength increases by ~24.5%, which can be attributed to the solution strengthening of Si in α(Al). The average fracture toughness values are 15.0 and 12.7 MPa·m1/2 for α(Al) in BM and RZ, respectively.
{"title":"Effect of TIG surface remelting on microstructure and mechanical properties of ZL109G Al alloy","authors":"Si-zhe NIU , Ze-long WANG , Zi-xuan CHEN , Ran ZONG , Bao-tao CHI , Jun WANG , Shi-ying LIU , Yun-wu MA , Shan-qing HU","doi":"10.1016/S1003-6326(25)66905-6","DOIUrl":"10.1016/S1003-6326(25)66905-6","url":null,"abstract":"<div><div>TIG surface remelting was performed to strengthen the surface of ZL109G alloy piston. The macrostructure indicates that surface remelting leads to the production of a remelted zone (RZ). The diameter of the primary Si decreases from 65.8 μm in the base metal (BM) to 7.1 μm in RZ. The grain size of the RZ is refined to be approximately one-seventh that of the BM. The cellular microstructure in the RZ is characterised by the α(Al) in the centre and intermetallics preferentially located at the cellular boundaries. The results of the mechanical properties demonstrate that the average hardness value of RZ increases by 39% compared to that of BM. For the transverse samples, the ultimate tensile strength increases by ~24.5%, which can be attributed to the solution strengthening of Si in α(Al). The average fracture toughness values are 15.0 and 12.7 MPa·m<sup>1/2</sup> for α(Al) in BM and RZ, respectively.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 11","pages":"Pages 3662-3676"},"PeriodicalIF":4.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-10-01DOI: 10.1016/S1003-6326(25)66889-0
Xin-yan TENG , Guo-qing CHEN , Ge ZHANG , Yang XIANG , Xue-song LENG
Insufficient metallurgical compatibility between Zr and Ni can lead to the formation of brittle welds and introduce thermal stress-related challenges during the electron beam welding process. Through the implementation of beam deflection and vibration, a transformation was achieved in the primary Ni5Zr dendrite structure, transitioning from a mass into a layered configuration, consequently resulting in the formation of an ultrafine-grained eutectic-dendrite complex structure. It is revealed that the enhanced strength-ductility synergy of this structure significantly contributes to the high tensile strength and improved plasticity observed in the welded joints. As a result, the welding cracks are effectively mitigated, and notable advancements are achieved in the mechanical properties of Zr/Ni joints, elevating the tensile strength of the joints from 36.4 to 189 MPa. This research not only highlights the potential of this technique in enhancing the strength and ductility of Zr/Ni welded joints but also serves as a valuable reference for future investigations involving welding applications of dissimilar metals.
{"title":"Enhanced strength-ductility synergy of ultrafine-grained eutectic-dendrite complex structures in zirconium/nickel electron beam welded joints","authors":"Xin-yan TENG , Guo-qing CHEN , Ge ZHANG , Yang XIANG , Xue-song LENG","doi":"10.1016/S1003-6326(25)66889-0","DOIUrl":"10.1016/S1003-6326(25)66889-0","url":null,"abstract":"<div><div>Insufficient metallurgical compatibility between Zr and Ni can lead to the formation of brittle welds and introduce thermal stress-related challenges during the electron beam welding process. Through the implementation of beam deflection and vibration, a transformation was achieved in the primary Ni<sub>5</sub>Zr dendrite structure, transitioning from a mass into a layered configuration, consequently resulting in the formation of an ultrafine-grained eutectic-dendrite complex structure. It is revealed that the enhanced strength-ductility synergy of this structure significantly contributes to the high tensile strength and improved plasticity observed in the welded joints. As a result, the welding cracks are effectively mitigated, and notable advancements are achieved in the mechanical properties of Zr/Ni joints, elevating the tensile strength of the joints from 36.4 to 189 MPa. This research not only highlights the potential of this technique in enhancing the strength and ductility of Zr/Ni welded joints but also serves as a valuable reference for future investigations involving welding applications of dissimilar metals.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 10","pages":"Pages 3414-3427"},"PeriodicalIF":4.7,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-10-01DOI: 10.1016/S1003-6326(25)66884-1
Hai-rui ZHANG , Hong-zhi NIU , Chao YANG , Nan XIANG , De-liang ZHANG , Fu-xiao CHEN
A unique discontinuous lamellar microstructure of titanium alloys consisting of lamellar colonies at prior β-Ti grain boundaries and internal interwoven α-laths is prepared by a TiH2-based powder metallurgy method. The α-variants get various crystallographic orientations and become discontinuous during vacuum annealing at 700 °C. Remarkably, nanoscale phaseδ-TiH compound layers are generated between α-laths and β-strips, so that dislocations are piledup at the α/δ/β interfaces during tensile deformation. This leads to dislocation slips being confined to individual α-laths, with different 〈a〉 slips and particularly pyramidal 〈c+a〉 slips being activated. The efficiency of wavy slip is promoted and the work hardening rate is enhanced. Finally, the combined effect of dispersed micro-shear bands and lath distortions is considered contributive for alleviating the stress concentration at grain boundaries, resulting in a high-promising synergy of enhanced ultimate tensile strength of 1080 MPa and good elongation to fracture of 13.6%.
采用tih2基粉末冶金法制备了一种由β-Ti晶界上的层状集落和内部交织的α-板条组成的独特的非连续层状钛合金显微组织。在700℃真空退火过程中，α-变异体出现了不同的晶体取向和不连续。在拉伸变形过程中，α-板条和β-条条之间形成纳米级相δ- tih复合层，使位错在α/δ/β界面处堆积。这导致位错滑移局限于单个α-板条，不同的< a +a >滑移，特别是锥体< c+a >滑移被激活。提高了波滑效率，提高了加工硬化率。最后，分散的微剪切带和板条变形的共同作用被认为有助于缓解晶界应力集中，从而提高了1080 MPa的极限抗拉强度和13.6%的良好断裂伸长率。
{"title":"Origin of high strength and good ductility of TiH2-based powder metallurgy titanium alloy with discontinuous lamellar structures","authors":"Hai-rui ZHANG , Hong-zhi NIU , Chao YANG , Nan XIANG , De-liang ZHANG , Fu-xiao CHEN","doi":"10.1016/S1003-6326(25)66884-1","DOIUrl":"10.1016/S1003-6326(25)66884-1","url":null,"abstract":"<div><div>A unique discontinuous lamellar microstructure of titanium alloys consisting of lamellar colonies at prior <em>β</em>-Ti grain boundaries and internal interwoven <em>α</em>-laths is prepared by a TiH<sub>2</sub>-based powder metallurgy method. The <em>α</em>-variants get various crystallographic orientations and become discontinuous during vacuum annealing at 700 °C. Remarkably, nanoscale phase<em>δ</em>-TiH compound layers are generated between <em>α</em>-laths and <em>β</em>-strips, so that dislocations are piledup at the <em>α</em>/<em>δ</em>/<em>β</em> interfaces during tensile deformation. This leads to dislocation slips being confined to individual <em>α</em>-laths, with different 〈<em>a</em>〉 slips and particularly pyramidal 〈<em>c</em>+<em>a</em>〉 slips being activated. The efficiency of wavy slip is promoted and the work hardening rate is enhanced. Finally, the combined effect of dispersed micro-shear bands and lath distortions is considered contributive for alleviating the stress concentration at grain boundaries, resulting in a high-promising synergy of enhanced ultimate tensile strength of 1080 MPa and good elongation to fracture of 13.6%.</div></div>","PeriodicalId":23191,"journal":{"name":"Transactions of Nonferrous Metals Society of China","volume":"35 10","pages":"Pages 3342-3356"},"PeriodicalIF":4.7,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号