Alloy design of intermetallic dispersion strengthened aluminum systems by mechanical alloying for high temperature applications

Abstract

Good interfacial bonding between the matrix and the second phase is very important and may be guaranteed by the low lattice mismatch between them. In this study, trialuminide intermetallics such as tetragonal D0(22) and D0(23) with Al3M (M=Ti, V, Zr) or cubic L1(2) with Al66Mn9(Ti, Zr)(25) were chosen as second phases to be dispersed on the basis of MEAM (Modified Embedded Atom Method) simulations. Specific compositions were determined based on thermodynamic calculations. Alloys were mechanically alloyed using Al powders and intermetallic powders that were separately fabricated. Hot pressed samples under vacuum were analyzed in terms of phase formation during heat treatment and were tested in compression at room temperature and 693K. Specimens showed enhanced strength with a yield strength of 800-920MPa at room temperature and 190-260MPa at 693K. Observation of no phase change during heat treatment indicated high thermal stability of the microstructure.