Xiuying GAI Jiabao LI Zengqiao KANG State Key Lab.for Fatigue and Fracture of Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
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110015
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ChinaJiawen HE Xi'an Jiaotong University
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Xi'an
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710049
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China
材料科学技术（英）
Surface yielding of metallic material was measured with strain gage and X-ray diffraction methods. The results show that.when the residual stress in the transverse direction is involved,the surface yield strength should be evaluated with biaxial Mises criterion.For a medium carbon high strength steel, the yield strength of the bulk material is 581 MPa and the surface yield strengths for 0.05% and 0.1%plastic strain are about 436 MPa and 463 MPa respectively.The 0.05% yield strength will approximately increase to 788 MPa after shot peening.In the early stage of plastic deformation, strain hardening in the surface layer is quite different from that of the bulk sample.
关键词:
biaxial stress
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null
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null
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null
PEI Hongxun Institute of Corrosion and Protection of Metals
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Academia Sinica
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Shenyang
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China Institute of Corrosion and Protection of Metals
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Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
Based on the experimental study of complex biaxial mode Ⅰ fatigue crack growth and the discussion on Von Mises'theory,a new approach is proposed for correlating crack propaga- tion rate under both in-phase and out-of-phase biaxial stress cycling.The results emphasize the contribution of plasticity to fatigue crack growth.
关键词:
biaxial stress
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null
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null
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null
覃
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明
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嵇宁
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李家宝
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马素媛
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陈昌荣
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宋忠孝
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何家文
金属学报
利用X射线拉伸实验研究了具有二维残余应力的Cu附着膜的屈服强度与退火温度的关系. 结果表明, Cu附着膜的条件屈服点随着退火温度的增高而减小, 退火温度在150---300 ℃间变化时, 减小幅度最大, 出现明显的拐点.这主要由于Cu附着膜在该温度范围内发生了再结晶, 使得原有的大部分组织结构强化因素消失了. Cu附着膜的屈服强度远远高于块体Cu材的屈服强度.
关键词:
Cu膜
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biaxial stress
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yield strength
李维红
稀有金属材料与工程
脆性材料的破坏通常是瞬态快速断裂,亚临界慢裂纹扩展特别是宏观慢扩展,很难在实验中观察.它一定程度上制约了玻璃陶瓷等材料的失效过程分析和阻力特性研究.本研究利用MFPA2D(Material Failure Process Analysis)软件成功地模拟了玻璃类脆性材料在平面应力状态下承受单向、双向应力时的亚临界裂纹扩展全过程,着重研究了脆性材料的慢裂纹扩展和扩展速度所受双向应力的影响,并讨论这种影响的机理和作用.通过声发射特性的数值模拟得到脆性材料在单向及双向应力状态下的亚临界裂纹扩展长度-荷载步曲线.结果表明,平行于裂纹面的拉应力对裂纹扩展有一定程度的阻碍作用,而平行于裂纹的压应力对裂纹有驱动效果.该数值实验结果与相关的实验结果取得了较好的一致,表明数值实验的可靠性,从而为脆性材料的可靠性和寿命评价提供理论基础和手段.
关键词:
脆性材料
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亚临界裂纹扩展
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数值模拟
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双向应力
