【摘 要】
：
系统研究了RRA处理过程回归制度对7A20铝合金组织性能的影响,测试了力学性能和电导率,利用OM和TEM(HRTEM)表征了晶界和晶内的微观组织结构.结果表明:在160℃的回归温度下,随回归时间的延长,抗拉强度由630 MPa降低到525 MPa;经120℃保温12 h的再时效处理后,抗拉强度由645 MPa升高到710 MPa;回归时间越长,再时效引起的强度增量越大,80 min时达到最大值185 MPa.在200℃的回归温度下,回归时间为10 min时,便达到峰值强度715 MPa.随回归温度提高,导
【机 构】
：
烟台南山学院 工学院,山东 烟台 265713;山东南山铝业股份有限公司 国家铝合金压力加工工程技术研究中心,山东 烟台 265706
论文部分内容阅读
系统研究了RRA处理过程回归制度对7A20铝合金组织性能的影响,测试了力学性能和电导率,利用OM和TEM(HRTEM)表征了晶界和晶内的微观组织结构.结果表明:在160℃的回归温度下,随回归时间的延长,抗拉强度由630 MPa降低到525 MPa;经120℃保温12 h的再时效处理后,抗拉强度由645 MPa升高到710 MPa;回归时间越长,再时效引起的强度增量越大,80 min时达到最大值185 MPa.在200℃的回归温度下,回归时间为10 min时,便达到峰值强度715 MPa.随回归温度提高,导电率先升高后降低,与回归时间呈正相关关系.经160、200和240℃下峰值强度对应的回归处理后,基体晶粒尺寸分别为55、65和70μm,相差不大.200℃ ×10 min的回归处理+再时效处理后,晶界处存在不连续的MgZn2相,尺寸在10～20 nm,与基体呈非共格关系;晶内存在弥散分布的纳米级η′强化析出相,与基体呈共格或者半共格关系;晶界处存在45～55 nm宽度的PFZ(Precipitation free zone)区.
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