离心压力对AZ31镁合金组织和力学性能的影响

Effect of centrifugal pressure on microstructure and mechanical properties of AZ31 magnesium alloy

通过XRD、压缩试验等方法研究了不同离心压力对AZ31镁合金组织演变和力学性能的影响。结果表明,随着离心压力的增大,离心铸造AZ31镁合金的晶粒明显细化,平衡凝固的共晶转变被抑制,第二相β-Mg17Al12析出量减少,由粗大的"骨骼"状分布转变成弥散分布在晶界,形成以过饱和初生相α-Mg为主相的凝固组织。XRD分析表明,离心压力的增大引起X射线衍射峰向高角度方向偏移,α-Mg的晶格常数减小。随着离心压力的增大,合金力学性能得到明显改善,抗压强度从199 MPa提高到256 MPa,而伸长率变化不明显。

Solidification microstructure evolution and mechanical properties of magnesium alloy AZ31 under different centrifugal pressure were investigated by XRD and compression test. The results show that with increase of centrifugal pressure,the grain size of centrifugal casting AZ31 magnesium alloy is refined and precipitation of the second phase β-Mg_（17）Al_（12） is decreased,and the morphology of β phase is from coarse bones to dispersed distribution in grain boundary,the main phase of solidification microstructure is supersaturated primary α-Mg.The XRD results show that increase of centrifugal pressure causes X-ray diffraction peak shift in the direction of high angle and the lattice constant of α-Mg decreases. With increase of the centrifugal pressure,mechanical properties are improved and the compressive strength of the alloy increases from 199 MPa to 256 MPa,while elongation change is not obvious.