Mg-4Zn-2Al-0.5Ca合金时效沉淀过程的相演变  

Evolution of aging precipitations of Mg-4Zn-2Al-0.5Ca alloy

作　　者：叶杰[1] 林小娉[1] 董允[1] 方杰[1] 王丽[1] 

机构地区：[1]东北大学材料与冶金学院,辽宁沈阳110819

出　　处：《材料热处理学报》2012年第4期22-26,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金资助项目(51141007);河北省自然科学基金资助项目(E2010001398)

摘　　要：利用高分辨透射电镜和扫描电镜分析了Mg-4Zn-2Al-0.5Ca合金时效沉淀过程中的相演变。结果表明:试验合金的时效硬化曲线呈现典型的时效硬化特征。试验合金在160℃时效达到峰值硬度时其沉淀相有:平行于(0001)Mg的圆盘状沉淀相、(梳齿状)块状沉淀相以及大量的亚稳过渡相。随时效时间的延长,生成长条状相,但基体中依然存在很多后析出的细小的弥散分布的粒状沉淀相。120℃×230 h时效处理后的微观组织中存在着蜂窝状组织,宽度为3～4 nm的长条状沉淀相,直径为5～7 nm的球状沉淀相;这些沉淀相的存在大大提高了合金的硬度。Evolution of precipitated phases in the process of ageing treatment of Mg-4Zn-2Al-0.5Ca alloy was investigated by transmission electron microscopy（TEM） and scanning electron microscopy（SEM）.The results indicate that precipitation hardening curves of the alloy show a typical characteristic of aging at different temperatures.The alloy reaches peak hardness,containing disc shaped and block shaped precipitates and a large number of metastable transition phase after ageing at 160 ℃ for 108 h.With prolonging of aging time,elongated precipitates are formed,but a lot of fine and dispersively distributed precipitate particles are still observed in the matrix.The microstructure of the alloy is honeycombed with long strip-shaped precipitates about 3-4 nm in width and disc precipitates about 5-7 nm in diameter after ageing at 120 ℃ for 230 h.These precipitates significantly increase the hardness of the alloy.

关 键 词：时效硬化 沉淀相 峰值硬度 

分 类 号：TG146.22[一般工业技术—材料科学与工程]