触变注射成型工艺对AZ91D组织与性能的影响

Effect of the Process Parameters of Thixomolding on the Microstructure and Mechanical Property of AZ91D

考察了料筒温度、回料转速、注射速度、模具温度等主要工艺参数对触变注射成型AZ91D镁合金组织与性能的影响。结果表明,料筒温度增加,固相率降低,蔷薇态形状的固相晶粒转化为颗粒状或近球状的晶粒;回料转速越大,所得到的组织越细小,固相组织由蔷薇状变球化圆整,同时回料转速较低时,半固态浆料中的固相率有增高的趋势;注射速度增大,组织逐渐细化,同时孔洞缺陷相对减少;随着模具温度的降低,触变注射成型产品的抗拉强度升高,伸长率变大,但过低的模具温度会导致孔洞缺陷数量的增加。

This paper presents the investigations of major processing parameters,such as bandheater temperature,rotary speed,injection speed,mould temperature etc.,on micro structure and properties of thixotropic injection molding Mg alloy AZ91D.The investigations show that with increase of bandheater temperature,solid phase rates decrease and transformation from rosebush form solid phase crystal grains to particles or close-spherical crystal grains is appeared,when rotary speed gets faster,the microstructure gets smaller and fine,its solid phase becomes spherical grains from rosebush form,and at the meantime ,cavity default decreases comparatively,along with decrease of molding temperature,the strength of thixotropic injection products increase,its elongation also increases,overlow temperature of mould will give a quantity increase of cavity default.