Mg-8Zn-1Cu-0.2Cr-0.5Ce-0.5Sb合金时效微观组织

Microstructure of Aging Mg-8Zn-1Cu Magnesium Alloy with Cr,Ce and Sb Compound Addition

利用HRTEM研究了复合添加Cr、Ce和Sb的Mg-8Zn-1Cu合金的时效微观组织。结果表明:在160℃经8 h时效的实验合金时效初期存在较高的硬化速率,其微观组织中存在层错和位错等缺陷,Moiré条纹,与基体共格且无明显边界的短杆状预沉淀相和在三叉晶界交合处析出的沉淀相;经20 h时效处理后达到峰值硬度945 MPa,其微观组织中存在大量短杆状'1-MgZn2相,块状'1-MgZn2相和粒状沉淀相;经48 h时效处理后,其微观组织中存在大量沿[0001]α方向生长的长条状沉淀相和弥散分布的粒状沉淀相,与Mg-8Zn-1Cu合金相比长条状沉淀相的尺寸明显减小。

The microstructure of aging Mg-8Zn-lCu magnesium alloy with Cr, Ce and Sb compound addition was studied by HRTEM. The results show that the hardening rate of the aging Mg-8Zn-lCu-0.2Cr-0.SCe-0.5Sb alloy is relatively high in the initial stage of the aging. For the alloy aged at 160 ℃ for 8 h, a number of stacking faults, dislocations and moir6 fringe come into existence, and the short rod-shaped pre-precipitates in the grains and the precipitates in the Irigeminal grain boundaries are simultaneously formed. For the alloy aged at 160 ℃ for 20 h, its peak hardness reaches 945 MPa and the alloy consists of a large number of short rod-shaped β1-MgZn2 precipitates, blocky ,β1 -MgZn2 precipitates and granular precipitates. When the alloy is aged at 160 ℃ for 48 h, it consists of a large number of elongated precipitates and granular precipitates. The elongated precipitates are formed perpendicularly to the basal plane of magnesium. Compared to the Mg-8Zn-lCu alloy, the sizes of elongated precipitates become much smaller.