镍基单晶合金涡轮叶片榫头裂纹尖端应力场及扩展趋势

采用率相关晶体滑移有限元程序,考虑单晶材料晶体取向的影响,对镍基单晶合金涡轮叶片榫头裂纹特性进行有限元分析.分别计算了榫头裂纹在各向同性条件以及{001},{011},{111}三种不同晶体取向下裂纹尖端的Mises应力分布,并判断了裂纹的扩展趋势.结果表明:镍基单晶合金涡轮叶片在{001}110],{011}110],{111}110]取向下的裂纹尖端均存在着明显的应力集中和较大的应力梯度,应力的最大值存在于裂纹尖端;{001},{011},{111}三种不同晶体取向的裂纹尖端的扩展开裂角分别为45°,54.7°,90°,说明镍基单晶合金涡轮叶片的裂纹扩展趋势受晶体取向的影响较大.

Stress field and propagation trend of crack tip in tenon of nickel-based single crystal superalloys turbine blade

A rate-dependent crystal slip finite element program was used to analyze the crack characteristic in tenon of nickel-based single crystal superalloys turbine blade, while the influence of crystallographic orientations was also taken into account. The Mises stress distributions of crack tip in tenon under isotropic condition combined with {001}, {011}, {111} crystal orientations were researched. Then the crack propagation trend was examined. The results show that: significant stress concentration and relatively large stress gradient occur in the crack tip with orientations of {001} 110], {011} 110], {111} 110]. The maximum stress value appears at the crack tip. Crack propagation trend varies with different crystallographic orientations. Under {001} 110],{011} 110], {111} 110] conditions, the crack propagation angle is 45°,54.7°,90°, respectively. It is clear that crystallographic orientation has significant influence on crack propagation trend of nickel-based single crystal superalloys turbine blade.