摘要
Mierostruetural development of a commercial 7055 (Al-Zn-Mg-Cu)alloy is studied by transmission electron mieroseope(TEM) during the process of single-ageing for up to 48 h. It is observed that Guinier-Preston (GP) zones are formed on { 111} planes when the sample is aged for a short time and grows up gradually with increase of ageing time. η' phase is formsed after ageing for 4 h at 120℃, having the orientation relationship with the matrix as[0 0 0 1]η'//[1 1^- 1]Al and (1 0 1^- 1)η'//(1 1 0)Al.η phase starts to occur after 24 h ageing and has an orientation relationship with matrix as [1^- 1 0 0]η//[1 1 0]Al and (0 0 0 1)η// (1 1 1)Al. Since the density of both η' phase and η phase particles is much lower than that of GP zone on aged alloy, GP zones are important to control the properties of the alloy.
采用透射电子显微镜对固溶单级时效处理7055铝合金中的沉淀相进行了研究。在较短的时效时间里,可以观察到GP区在{111}面上形成,随着时效时间增加,GP区逐渐长大。η′亚稳相在120°C时效4 h的时候被发现,它与基体的取向关系是[0 0 0 1]η′//[1 11]Al及(1 0 11)η′//( 1 1 0 )Al。在时效达到24 h时, η相便析出,它们与基体存在[ 1 1 0 0 ]η// [ 1 1 0 ]Al及(0 0 0 1)η//(1 1 1)Al的取向关系。由于η′亚稳相和η相颗粒的密度相比于区而言较小,所以GP区对提高该时效合金的强度和硬度起至关重要的作用。
基金
中南大学博士后基金资助项目~~