Thermal-Mechanical Fatigue of the Cast Aluminium Alloy GK-AlSi10Mg wa

Abstract

Cast aluminium alloys represent an important group of materials for practical use [1,2]. Their outstanding physical, mechanical and technological properties have well established them as common materials for important components of internal combustion engines in automotive engineering, e. g. engine blocks, cylinder heads and pistons [3]. The continuous efforts to increase power and to reduce exhaust emission, fuel consumption as well as weight lead to steadily increasing stresses in these components. Furthermore, they are subjected to thermal-mechanical fatigue (TMF) caused by transient processes like startups and shutdowns which result in thermally induced stresses and strains. Due to complex anisothermal loading the design and dimensioning of these components is a very demanding task. Commonly, for this purpose, material data from isothermal tests are employed. However, recently performed investigations show that lifetime predictions of thermal-mechanically loaded specimens based on data from isothermal experiments may be non-conservative to a large extent [4–9]. On the other hand, little information is available concerning the TMF-behaviour of cast aluminium alloys. The investigations carried out so far are limited to the determination of the number of cycles to crack initiation and to failure, respectively [10–16].