热挤压对Mg-6Al-1Ca-2.5Nd合金组织和性能影响

Effect of hot extrusion on the microstructure and mechanical properties of Mg - 6Al - 1Ca - 2. 5Nd alloy

以Mg-6Al-1Ca-2.5Nd合金为研究对象,通过重力金属型铸造方法获得Mg-6Al-1Ca-2.5Nd合金铸锭,并对该铸锭进行了均匀化处理和热挤压。通过金相显微镜、扫描电镜和万能拉伸试验机等分析、测试手段,研究了铸态、均匀化处理态和挤压态Mg-6Al-1Ca-2.5Nd合金显微组织和力学性能。试验结果表明,铸态Mg-6Al-1Ca-2.5Nd合金经均匀化处理后,显微组织变得更加均匀,金属间相含量减少;均匀化的Mg-6Al-1Ca-2.5Nd合金经热挤压后,晶粒尺寸和金属间相显著减小,金属间相分布更加弥散、均匀。与铸态Mg-6Al-1Ca-2.5Nd合金相比,挤压态Mg-6Al-1Ca-2.5Nd合金的抗拉强度和延伸率显著提高,提高幅度分别达41.2%和218.2%。

Mg -6A1 - 1 Ca -2.5Nd alloy was fabricated by gravity permanent mould. As - cast Mg -6A1 - 1 Ca -2.5Nd alloy was homogenized and hot extruded. The microstructure and mechanical properties of Mg -6A1 - 1 Ca -2.5 Nd alloy were observed and tested by optical microscope （ OM）, scanning electronic microscope（SEM） and universal tensiletesting machine. OM and SEM analysis showed that the grain size of homogenized Mg -6A1 - 1Ca - 2.5Nd alloy got finer and intermetallic phase decreased than that of as - cast. The grain size and intermetallic phase of Mg -6A1 - lCa -2.5Nd alloy got much finer and distributed more uniform after hot extrusion. The ultimate tensile strength and elongation of hot extruded Mg -6A1 - 1 Ca -2.5Nd alloy were higher than that of as - cast Mg -6A1 - 1Ca -2. 5Nd alloy and the increasing extent reached 41.2% and 218.2%, respectively.