| 摘要 |
PROBLEM TO BE SOLVED: To obtain a member having excellent energy absorbing characteristics by subjecting an Al-Mg-Si aluminum alloy extruded material contg. specified ratios of Mg, Si more surplus than the balance compsn. of Mg2Si and one or more kinds among Mn, Cr and Zr and having a fibrous structure to press quenching by air cooling and then aging treatment, thereby controlling its proof stress to a specific value or above. SOLUTION: This impact absorbing member consists of an Al-Mg-Si alloy extruded material contg., by mass, 0.30 to 0.70% Mg, 0.10 to 0.50% Si more surplus than the balance compsn. of Mg2Si and one or more kinds among Mn, Cr and Zr by 0.1 to 0.4% and having a fibrous structure and has >=210 N/mm2 proof stress. The total content of Si is preferably controlled to 0.5 to 0.7%, and, if required, 0.005 to 0.2% Ti and 0.10 to 0.40% Cu are desirable incorporated therein. The Al-Mg-Si alloy extruded material is subjected to press quenching by air cooling and is thereafter subjected to aging treatment to obtain >=210 N/mm2 proof strength suitable for an automotive frame structural material. |
