Microstructure of Mg-8Zn-4Al-1Ca aged alloy

The microstructure of Mg-8Zn-4Al-1Ca aged alloy was investigated by TEM and HRTEM. The results show that the hardening produced in the Mg-8Zn-4Al-1Ca alloy is considerably higher than that in the Mg-8Zn-4A1 alloy. A dense dispersion of disc-like Ca2Mg6Zn3 precipitates are formed in Mg-8Zn-4Al-1Ca alloy aged at 160 ℃ for 16 h. In addition, the lattice distortions, honeycomb-looking Moir＆#233; fringes, edge dislocations and dislocation loop also exist in the microstructure. The precipitates of alloy aged at 160 ℃ for 48 h are coarse disc-like and fine dispersed grainy. When the alloy is subjected to aging at 160 ℃ for 227 h, the microstructure consists of numerous MgZn2 precipitates and Ca2Mg6Zn3 precipitates. All the analyses show that Ca is a particularly effective trace addition in improving the age-hardening and postponing the formation of MgZn2 precipitates in Mg-8Zn-4Al alloy aged at 160 ℃.

Ti对建筑隔板镁合金挤压态组织和性能的影响

对建筑隔板用镁合金试样进行了挤压成形,研究了添加和不添加Ti元素对建筑隔板用镁合金试样的影响,并进行了显微组织、力学性能和耐腐蚀性能的测试、对比和分析。结果表明:与未添加元素Ti的Mg-3Al-1Zn合金相比,Mg-3Al-1Zn-0.8Ti合金的晶粒细化,抗拉强度和屈服强度分别增大14、37 MPa,质量损失率减小了37.15%,力学性能和耐腐蚀性能得到提升。Ti元素的添加有益于建筑隔板用Mg-3Al-1Zn镁合金综合性能的提升。