热处理对挤压Mg-5.5Zn-1.7Nd-0.7Cd-0.5Zr镁合金组织和性能的影响

Effects of Heat Treatment on Microstructure and Mechanical Properties of Extruded Mg-5.5Zn-1.7Nf-0.7Cd-0.5Zr Magnesium Alloy

采用光学显微镜及透射电镜研究了挤压变形Mg-5.5Zn-1.7Nd-0.7Cd-0.5Zr镁合金在不同热处理条件下的组织和性能。结果表明,经T6(固溶420℃×20h+时效200℃×20h)处理后,合金的抗拉强度和屈服强度低于挤压态,而经过T5(时效120℃×15h)处理后,高于挤压态;在T5工艺条件下,合金具有较好的力学性能,其抗拉强度σb=349MPa,屈服强度σ0.2=315MPa,伸长率δ=13%。

Effects of different heat treatment conditions on microstructure and mechanical properties of extruded Mg-5.5Zn-1.7Nf-0.7Cd-0.5Zr magnesium alloy were investigated by OM (optical microscope) and TEM (transmission electron microscope). The results indicate that ultimate tensile strength and yield strength of as-extruded alloy are superior to those of T6 treated ones (solid solution at 420℃ for 20 hours and aging at 200℃ for 20 hours), while it is lower than those of T5 treated ones (aging at 120℃ for 15 hours). Desirable mechanical properties of the T5 treated alloy can be observed, where tensile strength and yield strength as well as elongation reach 349MPa, 315MPa and 13%, respectively.