Influence of porosity on the fatigue limit of die cast magnesium and aluminium alloys
Influence of porosity on the fatigue limit of die cast magnesium and aluminium alloys
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DOI：
10.1016/s0142-1123(02)00054-3
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发表时间：
2003-03-01
影响因子：
6
通讯作者：
Stanzl-Tschegg, SE
中科院分区：
文献类型：
--
作者：
Mayer, H;Papakyriacou, M;Stanzl-Tschegg, SE
研究了高压压铸镁合金AZ91 hp、AM60 hp、AE42 hp、AS21 hp和类似生产的铸造铝合金AlSi9Cu3的高周疲劳性能。10(9)次循环的超声疲劳试验显示平均疲劳极限约为。38 ~ 50 MPa（镁合金）和75 MPa （AlSi9Cu3）。98.5%的试样在孔隙度处产生疲劳裂纹。将孔隙度视为初始裂纹，当超过临界应力强度幅值K-cr时，试件失效。镁合金的K-cr值为0.85+/-0.05 ~ 1.05+/-0.05 mparotm， AlSi9Cu3的K-cr值为1.85+/-0.10 mparotm。低于K-cr，疲劳裂纹可能在孔隙度处开始，但直到失效才扩展。利用K-cr，将缺陷的统计分布与不同应力幅值下的断裂概率联系起来。(C) 2002 Elsevier Science Ltd.版权所有。
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.