立方晶体单晶材料屈服面的研究  

STUDY ON THE YIELD SURFACE OF CUBIC CRYSTALLOID SINGLE CRYSTAL MATERIAL

作　　者：丁智平[1] 刘义伦[2] 尹泽勇[3] 杨治国[3] 成晓鸣[3] 

机构地区：[1]株洲工学院,株洲412008 [2]中南大学机电工程学院,长沙410083 [3]中国航空动力机械研究所,株洲412002

出　　处：《力学与实践》2004年第4期14-18,共5页Mechanics in Engineering

基　　金：湖南省自然科学基金项目(02JJY5014)资助

摘　　要：将Hill屈服准则用于:DD3镍基单晶合金屈服应力的预测,通过与试验结果比较发现,在760℃时的误差较大。根据立方单晶材料的屈服特点,用正应力偏张量平方与剪应力偏张量平方乘积项构成的应力不变量考虑单晶合金偏轴受载时存在的拉、剪应力耦合效应,提出了一个在工程上实用的新屈服准则。在新屈服准则中出现的参数可以通过单向拉伸试验确定,给出了确定这些参数的方法,并重新定义了适合新屈服准则的等效应力和等效应变。对各向同性材料,新屈服准则退化为Von Mises屈服准则,新定义的等效应力和 等效应变退化为Von Mises等效应力和等效应变。用新屈服准则对国产DD3单晶合金的屈服应力进行预测,能很好地符合试验结果;与Hill屈服准则比较,在760℃时的预测精度显著提高。Hill's yield criterion for plastically orthotropic solids is used to predict the yield stresses of single crystal Nickel-based superalloys DD3, but the correlation to experiments at 760° is poor. Taking into account the fact that the components of tension stresses are coupled with components of torsion stresses when off-axis loads are applied for an orthotropic material, Hill's yield criterion for plastically orthotropic solids is modified by adding an invariant which is composed of the quadratic product item of components of deviatoric stress tensor, and a new yield criterion is put forward in term of the characteristics of cubic single crystal material. The coefficients in the new criterion can be determined from uniaxial tension tests and the method of determining those coefficients is given in the paper. Equivalent stress and equivalent strain for the new criterion are defined. The new criterion, new equivalent stress and equivalent strain will be reduced to the von Mises's for isotropic material. The correlation to experiments is very good while the new criterion is used to predict the yield stresses of single crystal Nickel-based superalloys DD3, and it gives more accurate results than that of Hill's at 760°.

关 键 词：单晶合金 各向异性 屈服准则 屈服应力 

分 类 号：TG131[一般工业技术—材料科学与工程]