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Microstructure,mechanical properties and fracture behaviors of large-scale sand-cast Mg-3Y-2Gd-1Nd-0.4Zr alloy
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作者 Lixiang Yang Yuanding Huang +8 位作者 Zhengquan Hou Lv Xiao Yuling Xu Xiwang Dong Fei Li Gerrit Kurz Baode Sun Zhongquan Li Norbert Hort 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第8期2763-2775,共13页
In order to improve the ductility of commercial WE43 alloy and reduce its cost,a Mg-3Y-2Gd-1Nd-0.4Zr alloy with a low amount of rare earths was developed and prepared by sand casting with a differential pressure casti... In order to improve the ductility of commercial WE43 alloy and reduce its cost,a Mg-3Y-2Gd-1Nd-0.4Zr alloy with a low amount of rare earths was developed and prepared by sand casting with a differential pressure casting system.Its microstructure,mechanical properties and fracture behaviors in the as-cast,solution-treated and as-aged states were evaluated.It is found that the aged alloy exhibited excellent comprehensive mechanical properties owing to the fine dense plate-shapedβ'precipitates formed on prismatic habits during aging at 200℃for 192 hrs after solution-treated at 500℃for 24 hrs.Its ultimate tensile strength,yield strength,and elongation at ambient temperature reach to 319±10 MPa,202±2 MPa and 8.7±0.3%as well as 230±4 MPa,155±1 MPa and 16.0±0.5%at 250℃.The fracture mode of as-aged alloy was transferred from cleavage at room temperature to quasi-cleavage and ductile fracture at the test temperature 300℃.The properties of large-scale components fabricated using the developed Mg-3Y-2Gd-1Nd-0.4Zr alloy are better than those of commercial WE43 alloy,suggesting that the new developed alloy is a good candidate to fabricate the large complex thin-walled components. 展开更多
关键词 Magnesium alloy WE43 Large-scale sand-cast DUCTILITY
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Effect of heat treatment on microstructures and mechanical properties of sand-cast Mg-4Y-2Nd-1Gd-0.4Zr magnesium alloy 被引量:7
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作者 刘志杰 吴国华 +2 位作者 刘文才 庞松 丁文江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第7期1540-1548,共9页
Influence of heat treatment on the microstructures and mechanical properties of sand-cast Mg-4Y-2Nd-1Gd-0.4Zr magnesium alloy was investigated,and the tensile fracture mechanisms of the studied alloys under different ... Influence of heat treatment on the microstructures and mechanical properties of sand-cast Mg-4Y-2Nd-1Gd-0.4Zr magnesium alloy was investigated,and the tensile fracture mechanisms of the studied alloys under different conditions were also discussed.The results show that the optimum T4 and T6 heat treatment conditions for the as-cast Mg-4Y-2Nd-1Gd-0.4Zr alloy are 525°C,8 h and(525°C,8 h)+(225°C,16 h),respectively,with regard to the microstructure observation,DSC heating curve and mechanical properties.The hardness,yield strength,ultimate tensile strength and elongation of the Mg-4Y-2Nd-1Gd-0.4Zr alloy treated by optimum T6 heat treatment are HV91,180 MPa,297 MPa and 7.4%,respectively.Moreover,the Mg-4Y-2Nd-1Gd-0.4Zr alloys under different heat treatment conditions exhibit different tensile fracture modes. 展开更多
关键词 Mg-4Y-2Nd-1Gd-0.4Zr alloy sand-casting heat treatment mechanical property
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Influence of pouring temperature on solidification behavior, microstructure and mechanical properties of sand-cast Mg-10Gd-3Y-0.4Zr alloy 被引量:3
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作者 庞松 吴国华 +4 位作者 刘文才 张亮 张扬 Hans CONRAD 丁文江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第2期363-374,共12页
Influence of the pouring temperature ranging from 680 to 780 ℃ on the solidification behavior, the microstructure and mechanical properties of the sand-cast Mg-10Gd-3Y-0.4Zr alloy was investigated. It was found that ... Influence of the pouring temperature ranging from 680 to 780 ℃ on the solidification behavior, the microstructure and mechanical properties of the sand-cast Mg-10Gd-3Y-0.4Zr alloy was investigated. It was found that the nucleation undercooling of the a-Mg phase increased from 2.3 to 6.3 ℃. The average a-Mg grain size increased from 44 to 71 μm, but then decreased to 46 μm. The morphology of the eutectic compound transformed from a continuous network into a discontinuous state and then subsequently into an island-like block. The volume fraction of β-Mg_24RE_5 phase increased and its morphology transformed from particle into rod-like. The increase in pouring temperature increased the solute concentration. YS increased from 138 to 151 MPa, and UTS increased from 186 to 197 MPa. The alloy poured at 750 ℃ had optimal combining strength and ductility. The fracture surface mode transformed from quasi-cleavage crack into transgranular fracture, all plus the dimple-like fracture, with the micro-porosity and the re-oxidation inclusion as major defects. The average a-Mg grain size played a main role in the YS of sand-cast Mg-10Gd-3Y-0.4Zr alloy, besides other factors, i.e. micro-porosity, morphology of eutectic compounds, re-oxidation inclusion and solute concentration. 展开更多
关键词 sand-cast Mg alloys SOLIDIFICATION MICROSTRUCTURE mechanical properties
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Influence of cooling rate on solidification behavior of sand-cast Mg-10Gd-3Y-0.4Zr alloy 被引量:3
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作者 庞松 吴国华 +4 位作者 刘文才 张亮 张扬 Hans CONRAD 丁文江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3413-3420,共8页
The effect of the cooling rate ranging from 1.4 °C/s to 3.5 °C/s on the solidification behavior of the sand-cast Mg?10Gd?3Y?0.4Zr alloy was studied by computer aided cooling curve analysis (CA-CCA). With the... The effect of the cooling rate ranging from 1.4 °C/s to 3.5 °C/s on the solidification behavior of the sand-cast Mg?10Gd?3Y?0.4Zr alloy was studied by computer aided cooling curve analysis (CA-CCA). With the increase in cooling rate, the nucleation temperature (Tα,N) increases from 634.8 °C to 636.3 °C, the minimum temperature (Tα,Min) decreases from 631.9 °C to 630.7 °C, the nucleation undercooling (ΔTN) increases from 2.9 °C to 5.6 °C, the beginning temperature of the eutectic reaction (Teut,N) increases, the time of the eutectic reaction shortens, solidus temperature decreases from 546.0 °C to 541.4 °C, and solidification temperature range (ΔTS) increases by 6.1 °C. The increased nucleation rate (N&) is supposed to be the main reason for the increased?TN. Increased value (Teut,N?Teut,G) and shortened time of the eutectic reaction cause the change in the volume fraction and morphology of the second phase. 展开更多
关键词 Mg-10Gd-3Y-0.4Zr sand-cast cooling rate thermal analysis solidification behavior
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Effect of complex melt-refining treatment on microstructure and mechanical properties of sand-cast Mg–10Gd–3Y–0.5Zr alloy 被引量:3
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作者 梅俊 刘文才 +6 位作者 吴国华 张杨 张逸韬 洪毅恺 张若曦 肖旅 丁文江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1811-1821,共11页
The effect of complex melt-refining treatment (melt flux incorporating with rotating gas bubble stirring) on microstructure and mechanical behavior of the sand-cast Mg-10Gd-3Y-0.5Zr alloy was investigated. In additi... The effect of complex melt-refining treatment (melt flux incorporating with rotating gas bubble stirring) on microstructure and mechanical behavior of the sand-cast Mg-10Gd-3Y-0.5Zr alloy was investigated. In addition, the melt purifying mechanism of the complex melt-refining treatment for the sand-cast alloy was discussed systematically. The results show that the new melt-refining method can significantly improve melt quality and mechanical behavior of the tested alloy, i.e., compared to the reference unpttdfied alloy, the volume fraction of inclusions decreased from 0.47% to 0.28%, the ultimate tensile strength and elongation for T6-treated alloy increased from 245 MPa and 0.7% to 312 MPa and 4.5%, respectively. Especially, combining 1% flux with rotating gas bubble stirring can get even better purifying effectiveness than conventional sole 2% flux purification; the use of melt flux decreased by 50% and significantly reduced environmental pollution. 展开更多
关键词 magnesium alloy sand-cast PURIFICATION complex melt-refining mechanical property
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Microstructure and mechanical properties of repair welds of low-pressure sand-cast Mg?Y?RE?Zr alloy by tungsten inert gas welding 被引量:6
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作者 Xin Tong Guohua Wu +3 位作者 Liang Zhang Yingxin Wang Wencai Liu Wenjiang Ding 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2022年第1期195-209,共15页
The sand castings of Mg-Y-RE-Zr series alloys are widely utilized in the large scales and complex shapes in the aerospace industry,as a result of which there are always some cast defects in the products. In this study... The sand castings of Mg-Y-RE-Zr series alloys are widely utilized in the large scales and complex shapes in the aerospace industry,as a result of which there are always some cast defects in the products. In this study, the feasibility of repair welding of sand-cast Mg-4 Y-3 RE-0.5 Zr alloy by tungsten inert gas(TIG) welding was scrutinized with different welding currents from 150 to 210 A. The results indicated that defect-free repaired joints with good appearance could be acquired at 170 and 190 A. Interestingly, the grain size of the fusion zone(FZ) was refined initially and then increased with the linear increment of welding current. Because at the higher heat inputs, although the cooling rate of the molten pool was reduced, substantial constitutional supercooling for the grain refinement was attained after the Zr particles were transformed into Zr solutes. The tensile strength of the repaired joint at 170 A was 195 MPa with the maximum joint efficiency of 87.8%, and the elongation reached to 124.4% of the sand-cast base material(BM). However, serious grain coarsening and continuous eutectic structures generated in heat-affected zone(HAZ) above 190 A resulted in the weakening of the joint due to the brittle intergranular fracture. 展开更多
关键词 sand-cast Mg-Y-RE-Zr alloy Repair welding Microstructure Tensile properties Fracture behavior
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Effect of heat treatment on the microstructures and mechanical properties of the sand-cast Mg-2.7Nd-0.6Zn-0.5Zr alloy 被引量:4
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作者 D.Wu Y.Q.Ma +1 位作者 R.S.Chen W.Ke 《Journal of Magnesium and Alloys》 SCIE EI CAS 2014年第1期20-26,共7页
The tensile testing bars of the Mg-2.7Nd-0.6Zn-0.5Zr(wt.%)alloy were prepared by sand casting.The effect of solution temperature and aging time on the microstructures and mechanical properties were investigated.The as... The tensile testing bars of the Mg-2.7Nd-0.6Zn-0.5Zr(wt.%)alloy were prepared by sand casting.The effect of solution temperature and aging time on the microstructures and mechanical properties were investigated.The as-cast alloy was composed ofαmagnesium matrix and Mg12Nd eutectic compounds.After solution treatment at 500℃ for 18 h,the volume fraction of eutectic compounds decreased from∼7.8%to∼2.3%,and some small Zr-containing particles were observed to precipitate at grain interiors.As the solution temperature increased to 525℃ for 14 h,most of the eutectic compounds dissolved into the matrix.Peak-aged at 200℃ for 12 h,fineβ″particles was the dominant strengthening phase.The yield strength,ultimate tensile strength and elongation in the peak-aged condition were 191 MPa,258 MPa and 4.2%,respectively.Moreover,the Mg-2.7Nd-0.6Zn-0.5Zr alloys under different heat treatment conditions exhibited different tensile fracture modes. 展开更多
关键词 Magnesium alloy sand-cast Heat treatment MICROSTRUCTURE Mechanical properties
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Effect of heat treatments on microstructure and mechanical properties of sand cast Al−2Li−2Cu−0.5Mg−0.2Sc−0.2Zr alloy 被引量:2
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作者 Jin-shuo ZHANG Xiao-xiang ZHONG +2 位作者 Liang ZHANG Guo-hua WU Wen-cai LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第2期411-423,共13页
This study focused on modifying heat treatment schemes to enhance the mechanical properties of sand cast Al−2Li−2Cu−0.5Mg−0.2Sc−0.2Zr alloy.Different three-stage solution treatment schemes((460℃,32 h)+(520℃,24 h)+(5... This study focused on modifying heat treatment schemes to enhance the mechanical properties of sand cast Al−2Li−2Cu−0.5Mg−0.2Sc−0.2Zr alloy.Different three-stage solution treatment schemes((460℃,32 h)+(520℃,24 h)+(530/540/550℃,4/12/24/32 h))and aging temperatures(125,175,225℃)were designed for comparison.The microstructure evolutions were analyzed by optical microscopy(OM),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results showed that the three-stage solution treatment of(460℃,32 h)+(520℃,24 h)+(530℃,12 h)could dissolve most of the secondary phases.The TEM results illustrated that fineδ'(Al_(3)Li)particles were homogeneously distributed in the matrix after aging at 175℃for 8 h,accompanied by a small amount of lath-shaped S′(Al_(2)CuMg)and plate-like T_(1)(Al_(2)CuLi)phases.The best comprehensive properties of yield strength of 376 MPa,ultimate tensile strength of 458 MPa and elongation of 4.1%were obtained by the optimal heat treatment scheme((460℃,32 h)+(520℃,24 h)+(530℃,12 h)+(175℃,8 h)). 展开更多
关键词 Al−Li−Cu alloys sand-casting heat treatment PRECIPITATION microstructure mechanical properties
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Effects of substitution of Nd in a sand-cast Mg-2.5Nd-0.6Zn-0.5Zr alloy with x wt.% Sm(x=2.5, 4, and 6) 被引量:7
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作者 Deping Zhang Qiang Yang +4 位作者 Dongdong Zhang Kai Guan Fanqiang Bu Hong Zhou Jian Meng 《Journal of Rare Earths》 SCIE EI CAS CSCD 2017年第12期1261-1267,共7页
The microstructures and mechanical properties of a series of sand-cast Mg-Sm-Zn-Zr alloys under ascast, solution-treated and peak-aged states were thoroughly investigated. The OM, XRD, SEM and HRTEM were employed to c... The microstructures and mechanical properties of a series of sand-cast Mg-Sm-Zn-Zr alloys under ascast, solution-treated and peak-aged states were thoroughly investigated. The OM, XRD, SEM and HRTEM were employed to characterize the microstructural evolution. The results indicate that substitution Nd in the conventional Mg-2.5 Nd-0.6 Zn-0.5 Zr alloy with different contents of Sm has comparative grain refinement effect and will fully change the dominant intermetallic phase. In addition, the substituted alloys perform clearly higher strength with comparative ductility at both as-cast and peakaged conditions and much greater aging hardening response than the referential alloy. It is obvious that the strength increments of this alloy are attributed to the changes of the eutectic intermetallic particles on grain boundaries. 展开更多
关键词 Mg-Sm-Zn-Zr sand-cast Heat treatment Microstructure Mechanical property
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