添加Al-Ti-B的Mg-20Al-0.8Zn半固态组织的形成机理  

Effects of Al-Ti-B Addition on Semi-solid Microstructure Evolution in Isothermal Treatment Mg-20Al-0.8Zn Alloy

作　　者：阎峰云[1] 李波[2] 马孝斌[2] 那元真[2] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室 [2]兰州理工大学有色金属合金及加工教育部重点实验室

出　　处：《特种铸造及有色合金》2009年第3期230-232,共3页Special Casting & Nonferrous Alloys

摘　　要：利用添加质量分数为0.4%的Al-Ti-B中间合金来改善Mg-20Al-0.8Zn镁合金的铸态组织,研究了该合金在半固态等温处理过程中的组织演变以及非枝晶组织的制备与控制。结果表明,Al-Ti-B能显著减小铸态Mg-20Al-0.8Zn合金的晶粒尺寸,且经过Al-Ti-B细化处理的Mg-20Al-0.8Zn合金在半固态等温热处理过程中可获得更加均匀、细小的球状固相颗粒,固相颗粒的粗化速度较慢。试验得到的半固态组织中固相颗粒的平均尺寸为55～65μm。试验表明,采用等温处理(450℃+保温90～120min;465℃+保温90min或485℃+保温60～90min)能够得到更适合触变成形的半固态浆料,其半固态浆料的组织更加均匀、晶粒更加细小。The microstructural evolution and preparation as well as control of non-dendrite in the microstructure of the semi-solid Mg-20Al-0.8Zn magnesium alloy which was refined by Al-Ti-B master alloy were investigated during isothermal treatment process.The results indicate that grain size in as-cast microstructure of Mg-20Al-0.8Zn magnesium alloy can be greatly refined with Al-Ti-B addition.The more uniform and finer spheroidal particle phase in the Al-Ti-B refined semi-solid magnesium alloy can be observed after isothermal treatment,in which the spheroidized particle exhibits slowly coarsening tendency.The grain size with average diameters of 55～65 μm can be observed in the microstructure of the prepared magnesium.The semi-solid magnesium slurry more suitable for thixo-forming process can be obtained,and more uniformly distributed fine particles phase can be prepared with isothermal treatment at 450℃ for 90～120 min or at 465℃ for 90 min or 485℃ for 60～90 min.

关 键 词：镁合金 半固态等温处理 非枝晶 微观组织演变 

分 类 号：TG27[金属学及工艺—铸造]