Influence of the microstructure on the fatigue damage behaviour of the aluminium cast alloy AlSi7Mg0.3
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- 作者：Stephanie Siegfanz ; Stephanie.Siegfanz@hs-osnabrueck.de ; Alexander Giertler ; Wilhelm Michels ; Ulrich Krupp
- 关键词：Aluminium cast alloy AlSi7Mg0.3 (A 356) ; Fatigue crack growth ; Shape factor ; Eutectic silicon morphology
- 刊名：Materials Science and Engineering: A
- 出版年：2013
- 出版时间：10 March, 2013
- 年：2013
- 卷：565
- 期：Complete
- 页码：21-26
- 全文大小：1382 K
文摘
The influence of a variation in the heat treatment on the microstructure and the mechanical properties of the aluminium cast alloy AlSi7Mg0.3 (equivalent to A 356), in particular the fatigue mechanism, was studied. Grain refined and sodium-modified specimens were produced by die casting. Temperature and time for the solution heat treatment of cylindrical specimens were chosen in such a way that the strength of the ¦Á-solid solution could be varied while keeping the shape and size of the silicon precipitates in the eutectic area constant. The specimens were fatigue tested in a servohydraulic testing system under fully reversed loading (R=?1). Fatigue crack propagation was observed with a long distance microscope and was found to be shear-controlled in stage I. A qualitative correlation between the silicon particles and the crack propagation was found, i.e., eutectic areas cause deflections of the crack path and a decrease of the propagation rate. Specimens that were annealed at the highest solution heat treatment temperature exhibit a longer fatigue life.