FORGEABLE HYPEREUTECTIC Al-Si ALLOY MATERIAL HAVING HIGH TOUGHNESS

摘要

PROBLEM TO BE SOLVED: To provide a hypereutectic Al-Si alloy material whose brittle and hardly workable characteristics are improved, and to provide its production method.;SOLUTION: In the hypereutectic Al-Si based alloy material, a hypereutectic Al-Si based alloy comprising ≥18 mass% Si has a structure in which the eutectic structure is refined to ≤1 μm and the average crystal grain size of primary crystal Si to ≤20 μm. In the method for producing a hypereutectic Al-Si based alloy material, a hypereutectic Al-Si based alloy, e.g., an AC9A alloy is repeatedly subjected to rotary ECAP (Equal-Channel Angular Pressing) treatment at the temperature range of 375 to 425°C by a rotary ECAP process so as to obtain the hypereutectic Al-Si based alloy material having the above structure. The alloy has improved toughness and elongation and can be fed to forging and superplastic working, thus can be used for a member requiring homogeneity/reliability such as precision mechanical equipment.;COPYRIGHT: (C)2006,JPO&NCIPI