アルミナ短繊維化Ｍｇ‐４ｍａｓｓ％Ｚｎ‐ＲＥ合金複合材料の組織および引張特性に及ぼす繊維体積率の影響

Abstract

ZE41 magnesium alloy matrix composites reinforced with alumina short fibe were fabricated by using a squeeze casting method. In the previous studies, it has been cleared that tensile strength of the Mg-Zn alloy matrix composites at room temperature increases by both adding rare earth elements and a heat treatment, but not at 250°C. In the present studies, a fiber volume fraction was increased to improve high temperature strength. The effects of fiber volume fraction on structures and mechanical properties of the composites were investigated. The experimental values were also compared with the estimated ones based on the rule of mixture. As a reeult, an MgO layer with 0.2-0.3μm in thickness is crystallized at the interface between the fiber and the matrix of the composites, and results in strong bonding. The composites with fiber volume fraction of 24% exhibit tensile strength of 160MPa at 250°C and more than 70GPa of elastic modulus. The values of tensile strength and elastic modulus of the composites at room temperature are in good agreement with those calculated values based on the rule of mixture, for the composites with fiber volume fraction of 14%. Whereas the experimental values are superior to calculated ones for the composites with fiber volume fraction over 14% due to change from a completely random orientation to two dimensional one.