Microscopic phase-dependent residual stresses in the machined surface layer of two-phase alloy
Microscopic phase-dependent residual stresses in the machined surface layer of two-phase alloy
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DOI：
10.1016/j.jmatprotec.2008.10.039
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发表时间：
2009-05
影响因子：
6.3
通讯作者：
T. Obikawa;Y. Takemura;Yasuhiro Akiyama;J. Shinozuka;H. Sasahara
中科院分区：
文献类型：
--
作者：
T. Obikawa;Y. Takemura;Yasuhiro Akiyama;J. Shinozuka;H. Sasahara
在加工多相合金的情况下，加工表面层中的残余应力取决于微观结构，所述残余应力影响疲劳裂纹成核和应力腐蚀开裂，特别是在用于发电的航空航天发动机和燃气涡轮机中。因此，当机械加工零件在临界应力条件和环境下使用时，应知道微观相相关的残余应力。本文建立了两相合金切削加工的有限元模型，以获得已加工表面层的残余应力。选择由不同体积分数的铁素体和共析珠光体组成的铁和钢作为待加工的工作材料。首先，证实了计算结果吻合良好的切屑形成和切削力与实验。然后，在不同的碳含量和组织的规则/随机排列的加工表面层的残余应力得到。结果表明，工件的显微组织对已加工表面残余应力分布有很大影响，珠光体上的拉伸表面残余应力远大于铁素体上的拉伸表面残余应力。对铁素体和珠光体条带排列的工件进行有限元加工，发现减小铁素体和珠光体条带的宽度可以降低残余应力峰值。
Residual stresses in the machined surface layer, which affect fatigue crack nucleation and stress corrosion cracking especially in aerospace engines and gas turbines for power generation, depend on microstructures in case of machining a multiple-phase alloy. Hence, the microscopic phase-dependent residual stresses should be known when a machined part is used under critical stress conditions and circumstances. In the present paper, finite element modeling of machining two-phase alloys has been developed for obtaining the residual stresses in the machined surface layer. Iron and steels, which consist of different volume fractions of ferrite and eutectoid pearlite, were selected as work materials to be machined. First, it was confirmed that the calculated results agree well in chip formation and cutting forces with experimental ones. Then, residual stresses in the machined surface layer were obtained for different carbon contents and regular/random arrangements of microstructure. As a result, it is found that the microstructure of the workpiece has a great influence on the residual stress distribution on the machined surface and that tensile surface residual stress on pearlite is much larger than that on ferrite. Finite element machining of the work material with stripe arrangement of ferrite and pearlite revealed that the peak of residual stress would be reduced by decreasing the width of stripes of ferrite and pearlite.