摘要
The microstructures and mechanical properties of Mg-6Zn-1Mn-4Sn-1.5Nd alloy subjected to extrusion and T5 treatment were investigated using optical microscopy(OM), X-ray diffractometer(XRD), scanning electron microscopy(SEM), electron back scattered diffraction(EBSD), transmission electron microscopy(TEM), hardness tests and uniaxial tensile tests. The results showed that the as-cast alloy consisted of α(Mg), Mn, Mg7Zn3, Mg2 Sn and Mg Sn Nd phases. Dynamic recrystallization has completed during the extrusion process and the average grain size was 7.2 μm. After T5 treatment, the strength increased obviously, the yield strength and ultimate tensile strength of as-extruded alloy were increased by 94 and 34 MPa, respectively. Microstructure characterization revealed that the improvement of strength was determined by the high number density of β′1 rods.
利用光学显微镜、X射线衍射仪、扫描电镜、电子背散射衍射、透射电镜、硬度以及力学性能测试等对挤压态和T5处理态的Mg-6Zn-1Mn-4Sn-1.5Nd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、Mg2Sn和MgS nN d相。挤压过程中完成动态再结晶,再结晶晶粒的平均尺寸为7.2μm。T5热处理显著提高挤压态合金的强度。合金的屈服强度和抗拉强度分别增加94 MPa和34 MPa。显微组织分析表明,合金强度的提高主要是由于时效过程中析出高密度的β′1杆状相。
基金
Project(2013CB632200)supported by the National Great Theoretic Research,China
Project(2011BAE22B01-3)supported by the National Sci&Tech Support Program,China
Project(2010DFR50010)supported by the International Cooperation,Sharing Fund of Chongqing University’s Large-scale Equipment,China