Mg-6Zn-1Mn-2Sn-0.5Ca合金挤压态和热处理态的组织与力学性能

Microstructure and mechanical properties of as-extruded and heat treated Mg-6Zn-1Mn-2Sn-0.5Ca

摘要:

利用光学显微镜、X 射线衍射仪、扫描电镜、透射电镜、硬度以及力学性能测试等对挤压态和时效处理的Mg?6Zn?1Mn?2Sn?0.5Ca 镁合金的显微组织和力学性能进行研究。研究结果表明：合金铸态的相组成为α-Mg, Mn, Mg7Zn3, Ca₂Mg₆Zn₃ 和CaMgSn相组成。挤压态组织为完全动态再结晶组织,晶粒尺寸约为2.8 μm。固溶时效处理(T6,180 ℃+10 h)后,合金的强度明显增加,屈服和抗拉分别为320 MPa 和390 MPa。合金强度的提高主要是由于晶界强化,固溶强化和析出强化作用。

Abstract:

The microstructures and mechanical properties of as-extruded and peak-aged Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca) alloy were studied using optical microscopy (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), hardness tests and uniaxial tensile tests. The results showed that the as-cast alloy consisted of α-Mg, Mn, Mg7Zn3, Ca2Mg6Zn3 and CaMgSn phases. The as-extruded ZMT612-0.5Ca alloy presented a totally recrystallized microstructure. The average grain size of extruded alloy was ~2.8 μm. After heat treatment, the strength increased obviously, the yield strength and ultimate tensile strength of as-extruded alloy were increased to 320 and 390 MPa, respectively. Strength enhancement was attributed to the grain boundary strengthening, solid solution strengthening and precipitation strengthening.