Fatigue crack propagation of magnesium alloy in biaxial stress fields
Fatigue crack propagation of magnesium alloy in biaxial stress fields
复制标题
DOI：
10.1117/12.599238
复制
发表时间：
2005-05
期刊：
影响因子：
--
通讯作者：
Yasumi Itoh;A. Shimamoto
中科院分区：
文献类型：
--
作者：
Yasumi Itoh;A. Shimamoto
为了研究非奇异应力循环对镁合金疲劳裂纹扩展特性Δki-da/dN的影响，在双轴和单轴加载条件下，采用十字形试件进行了镁合金的疲劳裂纹扩展试验。本研究使用的镁合金(AZ31B-O)为2.5 mm厚的板材。根据不同的热处理条件，有四种不同的板材。这些条件是(A)没有热处理(AZ31B-O)，(B)200度2小时(AZ31B-200)，(C)350度2小时(AZ31B-350)，以及(D)430度2小时(AZ31B-430)。综合试验发现，比双向应力比σX0/σY0对ΔKi-da/dN关系有显著影响。当双向载荷应力比为0.5时，镁合金的疲劳裂纹扩展速率变得非常缓慢。当然，在其他双轴载荷应力比下，疲劳裂纹扩展速度也受到一定程度的影响。结果表明，当双向载荷应力比为负时，疲劳裂纹扩展速率变快，而当双向载荷应力比为正时，疲劳裂纹扩展速率变慢。讨论了镁合金在双向应力场中的微观组织对疲劳裂纹扩展的影响。
Fatigue crack propagation tests of magnesium alloy were conducted under conditions of biaxial and uniaxial loading by using a cruciform specimen in a biaxial fatigue machine, in order to investigate the effect of non-singular stress cycling on the fatigue crack growth properties ΔKI -da/dN. The Magnesium alloys (AZ31B-O) used for this research are 2.5mm thickness plates. There are four different kinds of plates due to their heat treatment conditions. These conditions are (a) with no heat treatments (AZ31B-O), (b) 200-degree 2 hours (AZ31B-200), (c) 350-degree 2 hours (AZ31B-350), and (d) 430-degree 2 hours (AZ31B-430). From these comprehensive experiments, the remarkable effect was found in the specific biaxial load stress ratio σx0/σy0 on ΔKI -da/dN relation. When biaxial load stress ratio was 0.5, it turned out that the fatigue crack propagation rate of a magnesium alloy becomes very slow. Of course, in other biaxial load stress ratios, fatigue crack propagation velocity was influenced to some extent. It turned out that fatigue crack propagation rate becomes fast when a biaxial load stress ratio is minus, and it becomes slow when a biaxial load stress ratio is plus. Some discussion is made on the effect of microstructure on fatigue crack propagation of magnesium alloy in a biaxial stress field.