Abstract

In order to produce good wear resistance powder metallurgy Al-Si alloys with high strength, addition of glass forming elements of Ni and Ce in Al_81Si_19 alloy was examined using SEM, TEM, tensile strength and wear testing. The solubility of Si in aluminum increased with increasing Ni and Ce contents for rapidly solidified powders. These bulk alloys consist of a mixed structure in which fine Si particles with a particle size below 500 nm and very fine A1_3Ni, A1_3Ce compounds with a particle size below 200 nm are homogeneously dispersed in aluminum matrix with a grain size below 600 nm. The tensile strength at room temperature for Al_81Si_19, Al_78Si_19Ni_2Ce_0.5, and Al_76Si_19Ni_4Ce_1 bulk alloys extruded at 674 K and ratio of 10 : 1 is 281,521, and 668 ㎫ respectively. Especially, Al_73Si_19Ni_7Ce_1 bulk alloy had a high tensile strength of 730 ㎫. These bulk alloys are good wear-resistance bel ter than commercial I/M 390-T6. Specially, attactability for counterpart is very little, about 15 times less than that of the I/M 390-T6. The structural refinement by adding glass forming elements such as Ni and Ce to hyper eutectic Al_81Si_19 alloy is concluded to be effective as a structural modification method.d.tion method.

• Keywords: Nano structure;Al-Si-Ni-Ce alloy;Rapid Solidification;Gas atomization;Ultimate tensile strength;