Papers by Keyword: Al-Si-Ge

Abstract: The process of severe plastic deformation (SPD) makes it possible to reduce the grain size to the submicrometer or nanometer range in many metallic materials. When the SPD process is applied to age hardenable alloys, it may also be possible to control aging behavior. In this study, a technique of equal-channel angular pressing (ECAP) is used as an SPD process and aging behavior is examined on the three selected Al alloy systems such as Al-Ag, Al-Mg-Si and Al-Si-Ge. The microstructures are observed using transmission electron microscopy and the mechanical properties including hardness are measured. It is shown that the SPD process introduces unusual phenomena in the precipitation process and there should be a potential for enhancement of strength over the conventional age-hardening process or for improvement of ductility while keeping the high strength.

Abstract: In this study, we investigated the effects of a small addition of Cu (0.1%) or Ge (0.1%) on the microstructure and mechanical property of Al-Si alloys. The results are as follows. The size of precipitates in the Cu-added or Ge-added alloys is smaller than that in the binary alloy. The size of the precipitates at the grain boundary in the Cu-added or Ge-added alloys is larger than the size of the precipitates in the binary alloy. However, the number of the precipitates at the grain boundary in the Cu-added and Ge-added alloys is smaller than that in the binary alloy. It was found that a small addition of Cu or Ge has the effect of raising the fatigue strength under repeated tensile loading as well as the tensile strength.