Microstructure and Mechanical Properties of Gas Atomized Aluminum Alloy Powder Compact Densified by Pulsed Current Pressure Sintering Process

Abstract

A Pulsed current pressure sintering (PCPS) method was employed to sinter compacts of gas atomized Al–8%Ni–2%Mn–1%Cu–0.8%Zr–0.7%Ti–0.25%Mg alloy powder which consisted of Al–Al₃Ni eutectic and α-Al supersaturated solid solution due to high quenching rates. Results are as follows: (1) The sintered compacts had Al₃Ni precipitates on the boundaries of the initial Al particles. As those precipitates increased, the hardness of the compact decreased. Maximum value of hardness of the compact was HV200 and about 3 at% of Ni atom was excessively dissolved in this compact. (2) The hydrogen content was decreased from 60 to 20 ppm by employing the sintering schedule to remove the adsorbed gas on the particle effectively. The tensile strength of the sintered compact was increased to 500 MPa which was comparable with that of an extruded compact.