Characterization of strengthened rapidly quenched Zr-based alloys

Abstract

The nominal composition components of alloy Zr66.4Nb6.4Ni8.7Cu10.5Al8 (Alloy A) were fabricated and characterized. The strengthening of in-situ alloys depends on the role of both the glassy matrix and the second phases. The glass transition and the crystallization kinetics were studied using DSC and X-ray diffraction as a function of element distribution. The amorphous and semi-crystalline structures were identified with the existence of nano crystals in the alloy nominal compositions. The Elastic compression modulus were found to increase with transition to crystallite phase. Where as, the microhardness decreases dramatically with the change from crystalline to amorphous phase. The compression fracture surface shows classic veins behavior. In mode of continuous heating and adiabatic annealing the glass transition, T g , and the crystalline peak, T p , temperatures display a strong dependency on heating rate. The activation energy for glass transition and crystallization were determined as E g = 226 KJ/mol based on Kissinger method, but during the isothermal process E g = 121 KJ/mol.