Cold Isostatic Pressing and Sintering Behavior of (Al+12.5%Cu)3Zr Nanocrystalline Intermetallic Compound Synthesized by Mechanical Alloying

Abstract

To improve the ductility of mTEX>$(Al +12.5%Cu)<_3$</TEX>Zr intermetallics, which are the potential high temperature structural materials, the mechanical alloying behavior, the effect of pressure and temperature on the <TEX>$Ll_2$</TEX>, phase formation and the behavior of the cold isostatic press and sintering were investigated. However mechanically alloyed A1<TEX>$_3$</TEX>Zr alloy have been known to have high mechanical strength even at high temperature, its workability was poor. A method of solution is refined grain size and phase transformation from <TEX>$DO_{23}$</TEX> to <TEX>$Ll_2$</TEX>.<TEX>$ Ll_2$</TEX> structure TEX>$(Al+12.5%Cu)<_3$</TEX>Zr with nanocrystalline microstructure intermetallic powders where were prepared by mechanical alloying of elemental powders. Grain sizes of the as milled powders were less than 10nm (from transmission electron microscopy, TEM). Thermal analyses showed that <TEX>$Ll_2$</TEX> structure was stable up to<TEX>$ 800^{\circ}C$</TEX> for 1hour <TEX>$(Al+ 12.5%Cu)<_3$</TEX>Zr. <TEX>$(Al+12.5%Cu)<_3$</TEX>Zr has been consolidated by cold isostatic pressing (CIP 138, 207, 276, 414MPa) at room temperature and subsequent heat treatment at high temperatures where <TEX>$Ll_2$</TEX> structure was stable under vacuum atmosphere. The results showed that 94.2% density of Ll<TEX>$_2$</TEX> compacts was obtained for the (Al +12.5%Cu)<TEX>$_3$</TEX>Zr by sintering at 80<TEX>$0^{\circ}C$</TEX> for 1hour (under CIPed 207MPa). This compact of the grain size was 40nm.