AZ91D镁合金半固态静态剪切流变特征的研究

Study on Rheologic Properties of Semisolid AZ91D Alloys

为了研究镁合金在半固态下的流变特征,依据铸造合金的流变学原理,利用自制的模具,在电子万能试验机上对AZ91D镁合金半固态坯料进行了半固态静态剪切流变试验,分析了保温时间、原始组织等参数对流变特征的影响,建立了AZ91D镁合金半固态流变特征的H1—(N1/H2)—(N2/S)五元件机械模型.结果表明,在加载条件不变的情况下,变形速率随加载时间和保温时间的延长而增大;半固态状态下存在一个发生变形的临界剪切应力;临界剪切应力和最大剪切应力随保温时间的延长而减小.

In order to study the rheologic property of semisolid magnesium alloys, the rheologic properties of semisolid AZ91D alloys are tentative studied by universal electronic tester. It had analyzed the influence of holding time and structure on rheologic property through the rheologic principle of casting alloys, and educes that the rheologic properties of semisolid AZ91D alloys can be expressed by the five elements mechanical model： H1-（N1/H2）-（N2/S）. The results indicate that the deformation rate is increased with the increasing loading time and holding time, under the same loading rate; and that there is a critic stress to make the semisolid billet deformed, named critic shear stress. The critic shear stress and the maximum shear stress are decreased with the increasing holding time.