摘要
A new Al−4.87Mn−1.42Mg−0.63Sc−0.20Zr(wt.%)alloy was fabricated by selective laser melting(SLM)and its microstructure and mechanical properties before and after aging were investigated.The results show that at a laser power input of 300 W,increasing laser scanning speeds from 700 to 1500 mm/s improves the mechanical properties.In the meantime,the lattice distortion values increase from 0.15%to 0.31%,showing an increasing solute supersaturation.At a laser scanning speed of 1500 mm/s,the yield strength,ultimate tensile strength and elongation of the as-SLM alloys are 356 MPa,412 MPa and 17.7%,respectively.After aging at 350°C for 8 h,these values increase to 527 MPa,554 MPa and 10.4%,respectively.The contributions to the yield strength increments from the secondary Al6(Fe,Mn)needle-like phase and re-precipitated L12 structured Al6(Sc,Zr,Ti)nano-particles during aging are 74 and 79 MPa,respectively.As the aging temperature increases to 450°C,the dominant precipitation strengthening is attributed to the secondary Al6(Sc,Zr,Ti)nano-particles.
通过选区激光熔化技术制备一种新型Al−4.87Mn−1.42Mg−0.63Sc−0.25Zr(质量分数,%)合金,研究合金时效前后的显微组织和力学性能。结果表明:在300 W的激光功率下,随着激光扫描速度从700 mm/s增至1500 mm/s,合金的力学性能提高,与此同时,点阵畸变从0.15%增至0.31%,溶质原子过饱和程度增加。在1500 mm/s的激光扫描速度下,选区激光熔化合金的屈服强度、极限抗拉强度和伸长率分别为356 MPa、412 MPa和17.7%。经350℃时效8 h后,选区激光熔化合金的屈服强度、抗拉强度和伸长率分别达到527 MPa、554 MPa和10.4%。时效中重新析出的二次针状相Al6(Fe,Mn)和具有L12结构的Al6(Sc,Zr,Ti)纳米相分别贡献了74 MPa和79 MPa的屈服强度增量。当增加时效温度至450℃时,析出强化以Al6(Sc,Zr,Ti)纳米粒子占优势。
基金
supported by the Science and Technology Innovation Program of Hunan Province,China(No.2023RC3055)
the Natural Science Foundation of Hunan Province,China(Nos.2023JJ30671)
the Natural Science Foundation of Changsha City,China(No.Kq2208264)
the National Natural Science Foundation of China(No.51601229).
