通过对裂纹与晶内片层和晶界的交互作用的原位观察，研究了全层状组织TiAl基合金的断裂机制。结果表明：裂纹萌发和扩展方式不仅依赖于片层与拉伸轴的相对取向，还受晶界取向的制约。当片层与拉伸轴成较大角度时，沿片层裂纹扩展是通过主裂纹与沿片层微裂纹的连接及剪切的过程；而当拉伸轴近平行片层时，跨片层裂纹依靠对界面分离和跨片层微裂纹这两种形式的微裂纹的连接进行扩展的。纵向交叉晶界有利于断裂韧性的提高，而横向晶界则不利于材料断裂韧性。
The fracture mechanism of fully lamellar Ti-49at% Al alloy hasbeen investigated by studying the interactions between crack and lamel lae or grain boundary. The results indicate that the nucleation and propagation mechanism of crack depend on not only lamellar orientation in grain but also the type of grain boundary. As the angle between tensile axis and lamellae is rela tively large, main cracks propagate by nucleation, growth and linkage with inter facial microcracks. As the tensile axis is nearly parallel to the lamellae, tran slamellar cracks propagate by nucleation, growth and linkage with two types of m icrocracks, e.g.interface delamination and translamellar microcracks. Different types of grain boundary have different toughening effects on TiAl alloy, that is, interlock grain boundary nearly parallel to the tensile axis is beneficial to fracture toughness, and the grain boundary nearly perpendicular to the tensile axis is not beneficial.
参考文献
| [1] | Kim Y W;Dennis M D.[J].Journal of The Minerals,Metals & Materials Society,1991(01):40. |
| [2] | Enoki M et al.[J].Materials Science and Engineering,1995,A192/193:420. |
| [3] | Chan K S;Kim Y W .[J].Metallurgical and Materials Transactions A:Physical Metallurgy and Materials Science,1992,23:1663. |
| [4] | Chan K S et al.[J].Metallurgical and Materials Transactions A:Physical Metallurgy and Materials Science,1994,25A:1217. |
| [5] | 陆永浩,张永刚,乔利杰,王燕斌,陈昌麒,褚武扬.片层取向对Ti-49at%Al PST晶体断裂机制的影响[J].稀有金属材料与工程,2000(02):128-131. |
| [6] | Inui H et al.[J].Philosophical Magazine A:Physics of Condensed Matter:Structure,Defects and Mechanical Properties,1992,66(04):539. |
| [7] | Yoo M H et al.[J].Materials Science and Engineering,1995,A192/193:14. |
| [8] | Hu X Z;Mai Y W .[J].Applied Mechanics Reviews,1992,45:355. |
| [9] | Chan K S .[J].Metallurgical and Materials Transactions A:Physical Metallurgy and Materials Science,1993,24A:569. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%