Elastic and microplastic properties of Al-Si/Ge alloys obtained from levitated melts

Structure, density, Young's modulus temperature dependencies as well as Young's modulus and ultrasound damping as a function of vibration strain were studied for Al-Si and Al-Ge hypo- and hyper-alloys. Samples were obtained by fast cooling of a levitated melt. Aging of Al-Si alloy and recovery of Al-Ge properties were observed. These phenomena were explained by a transformation of bond type during formation of Si- or dissolving Ge-rich zones. Stress-strain curves of micro-deformation determined from acoustical tests and of macro-deformation by quasi-static bending tests were studied. Their concentration dependencies were explained by an effect of grain sizes of eutectic matrix and an effect of primary crystals.