含孔隙纳米晶体材料力学性能的计算模型  

Numerical Modeling for Mechanical Behavior of Porous Nanocrystalline Materials

作　　者：李政辉[1] 尹侠[1] 周剑秋[1] 

机构地区：[1]南京工业大学机械与动力工程学院

出　　处：《特种铸造及有色合金》2010年第9期810-812,共3页Special Casting & Nonferrous Alloys

基　　金：江苏省高校自然科学基金资助项目(05KJB1300421)

摘　　要：针对纳米晶体材料的微观结构,构建了一种复合相本构关系来描述纳米晶体材料的力学性能。纳米晶体材料由晶粒和晶界两部分组成,其中晶界相又包含两部分:晶界第一部分与晶界第二部分。晶界第一部分与晶粒应变相等,这两者的结合体又与晶界第二部分是等应力的,这更符合纳米晶材料的实际变形情况。然后,建立的模型被用以计算含孔隙纳米晶体材料的弹性模量,并将提出的计算含空隙纳米晶体材料弹性模量的模型拓展为描述纳米晶体材料小塑性变形条件下的应力-应变关系。计算结果与试验数据相比较表明,本模型可以较好地反映晶粒尺寸和孔隙率对纳米晶体材料弹性模量与屈服强度的影响。A mixture-based constitutive model was developed on the basis of the real mixture status of nanocrystalline materials to describe the mechanical properties of the materials. The nanocrystalline materials are composed of grain and grain boundary phases,and the grain boundary phases are assumed to have equivalent parts: part I and part Ⅱ. The strain of the part I is the same as that of the grain interior; meanwhile,the stress of the part Ⅱ is equals to the total stress of the grain and part I of the grain boundary,which is well in agreement with practical ones. Then the established model was applied to calculate the elastic modulus of porous nanocrystalline materials. Furthermore,the model is extended to describe the stress-strain relation with small plastic deformation. The model can predict the effects of grain size and porosity on the elastic modulus and yield strength of the nanocrystalline materials. The simulated results are well in agreement with experimental ones in small plastic strain range.

关 键 词：纳米晶体材料 弹性模量 屈服应力 

分 类 号：TB383.1[一般工业技术—材料科学与工程]