7n01铝合金的时效工艺及抗腐蚀性能研究材料加工工程专业论文.docxVIP

(3)7N01铝合金的抗晶间腐蚀、剥落腐蚀和应力腐蚀性能均与时效 (3)7N01铝合金的抗晶间腐蚀、剥落腐蚀和应力腐蚀性能均与时效 工艺密切相关，其敏感性由低到高依次为：双级时效、非等温时效、RRA、 T6时效、自然时效。 (4)7N01铝合金的抗腐蚀性能与晶界析出相(GBP)的结构、特性 及无析出带(PFZ)有关。双级时效、RRA和非等温时效合金的GBP均为 不连续分布的粗大11相，且PFZ宽度均大于68nm，因此降低了合金的腐蚀 敏感性。而自然时效和T6时效合金的GBP分别为连续分布的11 7和”相， PFZ不明显，腐蚀敏感性较高。 关键词：7N01铝合金时效工艺显微组织抗腐蚀性能 万方数据 STUDY STUDY oN THE AGING PRoCESS AND CoRRoSIoN RESISTANCE PRoPERTIES oF 7N01 ALUMINUM ALLoY ABSTRACT 7N0 1 aluminum alloy is one of the critical structural materials used in the fields such as modem aerospace and vehicle engineering，but the application ranges of this alloy are largely limited by the high susceptibility of localized corrosion．Aging treatment is the critical process during the manufacturing process of the alloy．Corrosion resistance as well as excellent mechanical properties may be achieved simultaneously by an appropriate aging treatment for the alloy．In this thesis，the aging processes of the alloy including peak—aging (T6)，two—stage aging，retrogression and re—aging(RRA)and non—isothermal aging have been investigated．Furthermore，the influences of aging process on the microstructure，inter-granular corrosion(IGC)，exfoliation corrosion (EXCO)，stress corrosion(SC)and electrochemical corrosion，have been analyzed．The relations between the microstructure and the corrosion properties of the alloy have been obtained．The main conclusions are as follows： (1)For 7N01 aluminum alloy,a T6 aging process with 120。C／24h led to a higher strength，and a two-stage aging process with 1 1 0。C／4+1 60。C／8h led to better corrosion resistance properties，while a RRA treatment process with 1 20。C／24h preaging，1 80。C／25min retrogression，and 1 20。C／24h re—aging，or a 万方数据 non—isothermal non—isothermal aging process with(40。C，180。C)@20。C／h+(180。C，120。C)@ 20。C／h led to better comprehensive properties． (2)The inter-granular corrosion of the alloy extended to the inside with the form of a mesh．The exfoliation corrosion of 7N0 1 aluminum alloy experienced the process described as pit