Microstructure and compressive behavior of Al-base amorphous/nanocrystalline alloys fabricated by powder forging

Al-base amorphous/nanocrystalline bulk alloy rods composed of Al-10Ni-6Ce (numbers indicate at.%) matrix alloy and Al-4Fe-0.6Mo-1.1V-0.3Zr alloy particles (volume fraction=0.3) were fabricated by a powder forging process. The starting materials were rapidly quenched, powder-shaped amorphous Al-10Ni-6Ce alloy and nanocrystalline Al-4Fe-0.6Mo-1.1V-0.3Zr alloy. The amorphous alloy powders were prepared by the pulverization of melt-spun ribbons, and the nanocrystalline alloy powders were fabricated by using a gas atomization technique. The powder forging process involved pre-compaction of the amorphous/crystalline powder mixtures by cold pressing and subsequent forging at temperatures ranging from 623 to 773 K with a pressure of 0.66 GPa and a strain rate of 10(-2) s(-1) to produce the rod-shaped bulk hybrid alloys having a diameter of 10 mm. Bulk monolithic A1-10Ni-6Ce alloys having the same shape were also fabricated by using a similar process to that used for the hybrid ones. Fully dense bulk rods with a porosity of less than 2% were achieved for all of the forged monolithic and hybrid alloys. A remarkably high compressive strength of about 1.2 GPa along with a compressive plastic strain of 1% was obtained at room temperature for the bulk hybrid specimen forged at 648-673 K. In contrast, the bulk monolithic specimen forged at 648-723 K did not exhibit any compressive plastic strain, although it possessed a very high compressive strength of approximately 1.34 GPa. (c) 2006 Elsevier B.V All rights reserved.