半固态金属触变挤压上限分析  

Upper bound analysis of thixotropic extrusion of semi-solid metal

作　　者：闫洪[1] 夏巨谌[2] 周冰锋[1] 

机构地区：[1]南昌大学机电学院,南昌330029 [2]华中科技大学模具技术国家重点实验室,武汉430074

出　　处：《塑性工程学报》2005年第4期66-69,共4页Journal of Plasticity Engineering

基　　金：江西省自然科学基金(0350005);华中科技大学塑性成形及模具技术国家重点实验室开放基金(048);江西省材料科学与工程研究中心开放基金(CL0207)资助项目。

摘　　要：运用半固态金属触变塑性成形上限法,对半固态金属触变挤压过程进行了上限分析。导出了半固态金属触变挤压上限功率的计算公式,获得了相对应力与摩擦因子、半锥角和断面缩减率等工艺参数的相互影响关系。对于某一固定的半锥角,摩擦因子的增加使相对应力增大,而增大的幅度随着断面缩减率的增大而增大。对于某一固定的断面缩减率,半锥角的增加,使相对应力下降后再度略有上升。因此存在着一个最佳半锥角,对应于最佳上限解,其相对应力为最小。而且摩擦因子越小,相对应力下降幅度越小。经实验验证,所获计算结果与实验值吻合,可用于指导半固态金属触变挤压工艺实践。The methodology presented to conduct the upper bound analysis of thixotropic extrusion process of semi-solid metal.The calculating formulas of deformed power were derived.The relationship among relative stress and frictional factor, die semiangle were obtained.The relative stress increases with increasing in the frictional factor, whose value increases with increasing in the area reduction ratio for a certain die semi-angle. The relative stress first decreases and then increases with increasing in the die semi-angle for a certain area reduction ratio.So, the optimal die semi-angle exists with the corresponding relative stress having the least value.The calculated results are agreement with the experimental ones, which are applied to directing technological practice of thixotropic extrusion of semi-solid.

关 键 词：半固态金属 挤压 上限分析 触变成形 

分 类 号：TG146.2[一般工业技术—材料科学与工程]