Phase transformation and properties of quasicrystal particles/Al matrix composites

来源期刊：中国有色金属学报(英文版)2000年第3期

论文作者：齐育红 张占平 黑祖昆 董闯

文章页码：358 - 363

Key words：composites; quasicrystals; aluminium alloys; phase transformation

Abstract: Diffusion-controlled phase transformations and tribological properties and hardness of Al₆₅Cu₂₀Cr₁₅quasicrystal particles(QC_p)/Al matrix composites have been studied. The mixtures of the quasicrystal particles with volume fractions of 15%, 20%, 25% , 30% and pure Al powder were hot-pressed at 600, 650, 700℃. During the diffusion-controlled phase transformation induced by hot-pressing, a simple cubic icosahedric quasicrystal (SIQC) phase transforms into stable phase with the microstructure of monoclinic of Al₁₃Cr₂through a transitional faced cubic icosahedric quasicrystal (FIQC), a decagonal quasicrystal (DQC) and an approximant of decagonal quasicrystal (DA) phases. And G. P. zones and Al-Cu precipitates,θ′-Al₂Cu andθ-Al₂Cu, are separated out from the Al matrix respectively after hot-pressing. The QC_p/Al composites have double-strengthening effect after hot-pressing. One is the strengthening of the particles that reinforce the matrix Al; the other is the dispersion strengthening of the precipitates in the Al matrix. The hardness of the composites increases with increasing volume fraction of quasicrystal particles. The maximum hardness reaches 1200MPa, being 4 times that of Al. The frictional coefficient and the wear rate of the QC_p/Al are lower than those of Al. In comparison with SiC_p/Al matrix composites, QC_p/Al composites have higher hardness and lower frictional coefficient.