粉末烧结材料屈服条件研究和进展

介绍了粉末烧结材料屈服条件研究现状和粉末烧结材料屈服条件基本形式，分析了几种典型的粉末烧结材料屈服条件，从临界弹性变形比能的角度说明了粉末烧结材料屈服的物理意义。基于粉末烧结材料屈服和变形的物理性质，揭示了粉末烧结材料后继屈服与应力球量、应力偏量、基体材料性质、粉末烧结材料初始相对密度、变形中的相对密度以及加工硬化之间的关系，进而建立了粉末烧结材料屈服条件和后继屈服务件的统一表达式。介绍了粉末烧结材料屈服条件的简化和应用，指出熔铸致密材料屈服条件是粉末烧结材料屈服务件的特例。通过算例求解了粉末烧结材料等静压变形力和纯剪变形力。结合烧结铜屈服、变形计算，将粉末烧结材料屈服务件外推到了松装粉末状态和全致密状态时，仍然符合实际情况。

Research and Progress of Yield Criterion for Sintered Powder Materials

The basic form of yield criterion and its research situation for sintered powder materials is briefly introduced. Several typical yield criterions for sintered powder materials are analyzed, the physical property of yield is explained from point of view of critical elastic deformation energy ratio. The effects of hydrostatic stress, deviatoric stress, matrix material property, initial and instant densities, and deformation strengthening on following yield of sintered powder material are revealed based on the physical law of yield and deformation, and a unified form of function for initial and following yield of sintered powder materials is derived. A simplified yield criterion and its application are discussed, and the special case of yield criterion for sintered powder materials, which expresses the yield criterion of fully dense material, is pointed out. The deformation pressures corresponding to isotropic pressing and pure shearing processes are calculated from the yield criterion for sintered powder materials. Furthermore the yield criterion for sintered powder materials is extended to the cases of loosely piled powder and fully dense material, it is in according with the fact of yield of loosely piled copper powder and fully dense copper.