T5处理对高真空压铸Al-10Si-Cu-Mg-Mn合金组织影响

Effects of T5 Heat Treatment on Microstructure of High Vacuum Die Casting Al-10Si-Cu-Mg-Mn Alloy

采用高真空压铸制备了不同Cu含量的AlSi10CuMgMn合金,采用光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)对铸态和T5态合金微观组织进行研究。结果表明,不同Cu含量下,铸态合金组织由α-Al、共晶Si和α-Fe、Q和θ相组成。随着Cu含量增加,Q相数量变化不大,形貌以层片状为主;θ相数量则逐渐增多,形貌由分散的粒状转变成聚集的块状。T5热处理不会改变相的类型和形貌,峰值时效时主要析出相为β"和θ’相,Cu含量较低时,析出相以β"相为主,Cu含量较高时,析出相以θ’相为主。

Al-10Si-Cu-Mg-Mn alloys with different Cu contents were prepared by high vacuum die casting process.The microstructure of as-cast and T5 alloys were investigated by OM,SEM and TEM.The results indicated that the microstructure of as-cast alloys consists ofα-Al,eutectic Si andα-Fe,Q andθphases.With the increase of Cu con⁃tent,the number of Q phase keeps stable,and the morphology is mainly lamellar.The amount ofθphase is gradually increased,and the morphology is changed from dispersed granular to aggregated blocky.T5 heat treatment cannot change phase types and morphology,and the main precipitated phases areβ″andθ′phases at peak aging condition.With a lower Cu contents,the precipitated phase is dominated byβ″and at higher Cu contents,the precipitated phase is dominated byθ′.