Temperature Dependence of Hardness and Expansion in an Icosahedral Al-Pd-Mn Alloy

Abstract

Temperature dependence of hardness and expansion in icosahedral Al 72 Pd 20 Mn 8 alloy ( i -AlPdMn) are examined in comparison with a cubic Al 60 Pd 25 Mn 15 alloy ( c -AlPdMn). The hardness at room temperature is about 780 kg/mm 2 for i -AlPdMn, much greater than that for c -AlPdMn of 420 kg/mm 2 , and decreases to about 200 kg/mm 2 at 973 K. The thermal expansion of i -AlPdMn is found to be linear versus temperature and the thermal expansion coefficient is estimated to be ∼14.6×10 -6 K -1 .