晶向和温度对含孔洞单晶TiAl-Nb合金断裂行为的影响

Effect of Crystal Orientation and Temperature on Fracture Behaviour of Single Crystal TiAl-Nb Alloys with Void

本工作采用分子动力学方法研究了晶向和温度对含孔洞单晶TiAl-Nb合金断裂行为的影响,主要分析了不同条件下TiAl-Nb合金的力学性能及微观缺陷演化。研究结果表明:晶向对含孔洞TiAl-Nb合金的力学性能有显著影响,但是对其断裂行为影响较小,这可能是因为Nb元素的加入导致的固溶强化作用大于位错的强化作用;温度越高,TiAl-Nb合金的屈服应力、屈服应变及杨氏模量越小,位错首次在孔洞处形核的时间越提前,位错数量及位错类型越少,材料失效时间越提前。

The effects of crystal orientation and temperature on the fracture behaviour of single crystal TiAl-Nb alloys with void were studied by molecular dynamics method.The mechanical properties and internal micro-defect evolution of TiAl-Nb alloys under different conditions were analyzed.The results show that,the crystal orientation has a significant effect on the mechanical properties of TiAll-Nb alloys with voids,but has little effect on the fracture behaviour of it,which is maybe due to the reason that the solid solution strengthening effect is greater than that of dislocation because of the addition of Nb element.The higher the temperature lead to the smaller yield stress,yield strain and Young's modulus of TiAl-Nb alloys,the time is earlier when the dislocations first nucleate at the void,the fewer number and type of dislocations,as well as the time of the material failure is earlier.