【摘要】 采用金属型铸造法,制备Sr含量0~1.2%(质量分数)的AZ31-xSr系列镁合金试样。采用OM、SEM、EDS、力学性能测试等方法研究其显微组织和力学性能,并结合DSC研究合金铸态组织的细化机制。结果表明:加入0.3%的Sr时,合金的显微组织得到了明显细化并有少量的Al4Sr生成,当Sr的含量进一步增加时,合金中的Al4Sr含量增加并呈粒状和杆状分布且使β-Mg17Al12弥散均匀分布;当Sr的含量为1.2%时,合金的晶界由连续网状的Al4Sr构成,并有少量的Mg-Al-Sr三元相生成。合金的常温力学性能在Sr含量为0.9%时达到最优,抗拉强度和延伸率分别为194MPa和7.6%,分别比AZ31提高了27.6%和36.8%。更多还原

【Abstract】 Effects of 0-1.2wt% strontium on microstructure and mechanical properties of metal mold cast AZ31B magnesium alloys were investigated by OM,SEM,EDS and tensile testing.The refinement mechanism of as-cast microstructure was studied by DSC.The results show that the addition of 0.3% Sr can obviously refine the grain size of the alloy and form a few of Al4Sr phase.When the content of Sr is added,the amount of Al4Sr phase is increased and presents granular and rod distribution resulting in β-Mg17Al12 distributing dispersion;when the addition of Sr is 1.2%,the grain boundary of the alloy consists of continuous reticulate Al4Sr and a spot of Mg-Al-Sr compound.When the content of Sr is 0.9%,the mechanical properties of the alloy reach to the maximum at room temperature,the ultimate tensile strength of the alloy is up to 194 MPa and the elongation of the alloys is also up to 7.6%.The ultimate tensile strength and the elongation of the alloy are enhanced by 27.6% and 36.8%,respectively.更多还原