Influence of porosity on the fatigue limit of die cast magnesium and aluminium alloys

被引:350
作者
Mayer, H [1 ]
Papakyriacou, M [1 ]
Zettl, B [1 ]
Stanzl-Tschegg, SE [1 ]
机构
[1] Univ Agr Sci, Inst Meteorol & Phys, A-1180 Vienna, Austria
关键词
cast magnesium; cast aluminium; porosity; high-cycle fatigue; fatigue limit;
D O I
10.1016/S0142-1123(02)00054-3
中图分类号
TH [机械、仪表工业];
学科分类号
0802 ;
摘要
High cycle fatigue properties of high-pressure die-cast magnesium alloys AZ91 hp, AM60 hp, AE42 hp, AS21 hp and of similarly produced cast aluminium alloy AlSi9Cu3 have been investigated. Ultrasonic fatigue tests up to 10(9) cycles show mean fatigue limits of approx. 38-50 MPa (magnesium alloys) and 75 MPa (AlSi9Cu3) in the tested casting condition. Fatigue cracks initiated at porosity in 98.5% of the samples. Considering porosity as initial cracks, specimens fail, if critical stress intensity amplitude, K-cr, is exceeded. K-cr of the magnesium alloys range from 0.85+/-0.05 to 1.05+/-0.05 MParootm and 1.85+/-0.10 Mparootm was found for AlSi9Cu3. Below K-cr, fatigue cracks may initiate at porosity, however, do not propagate until failure. Using K-cr, the statistical distribution of defects is linked to the fracture probability at different stress amplitudes. (C) 2002 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:245 / 256
页数:12
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