【作者】 徐云庆；

【导师】 孙仙奇；

【作者基本信息】 广西大学 ， 材料物理与化学， 2008， 硕士

【摘要】 7A04超高强铝合金广泛应用于航空和航天领域,是该领域重要的结构材料之一。国内外学者对高强高韧铝合金的热处理已进行了广泛的研究,追求材料的强度和解决由此带来的断裂韧性偏低的问题,一直是研究的主题。本文研究了热处理工艺对7A04超高强铝合金组织和性能的影响,探索出了两种可显著提高合金性能的热处理工艺T6a-17（485℃/50min/水淬+100℃/36h/时效）和T6a3-21（485℃/50min/水淬+160℃/10min+120℃/10min+60℃/240h/时效）;通过对合金室温拉伸性能测试、冲击韧性测试和断裂韧性测试得到的结果,分析了三者之间的联系;并对合金的显微组织进行观察,分析了合金性能提高的原因。得出了以下几点结论:1、与现行的规范热处理工艺T6a-10（485℃/50min/水淬+120℃/24h/时效）相比,采用T6a-17（485℃/50min/水淬+100℃/36h/时效）和T6a3-21（485℃/50min/水淬+160℃/10min+120℃/10min+60℃/240h/时效）的热处理新工艺,在合金的强度略有提高或没有明显下降的前提下,合金的韧性有了显著的提高,其中α_k分别提高了25.1%和54.5%,K_IC分别提高了20.8%和29.4%。2、拉伸性能、冲击韧性、断裂韧性之间存在着一定的对应关系,特别是冲击韧性与断裂韧性存在着密切的相关性。3、T6a-17工艺下合金的沉淀析出相比T6a-10工艺下的稍小,分布更均匀弥散;T6a3-21工艺下合金沉淀析出大小不同的析出相,这些析出相大小相间的分布在基体中。从而有效地提高了合金的冲击韧性和断裂韧性。更多还原

【Abstract】 7A04 ultra-high strength aluminum alloy is applied extensively in the domains of aviation and spaceflight,which is one of the most important structure materials.Heat treatment of high strength and toughness aluminum alloy has already been studied extensively by internal and external reseachers. Seeking high strength and high toughness aluminum alloy is a hot subject.In this paper,heat treatment crafts impacting on the microstructure and mechanical properties of 7A04 ultra-high strength aluminum alloy had been researched,two heat treatment crafts including T6a-17（485℃/50min/water quench+100℃/36h/aging）and T6a3-21（485℃/50min/water quench +160℃/10min+120℃/10min+60℃/240h/aging）which can markedly improve the mechanical properties of 7A04 alloy were found;The results obtained by testing the mechanical properties,impact toughness and fracture toughness of alloy in room temperature,were used to analyze their relationship;and the reason why the capabilities of 7A04 alloys were increased were found by observing the diversification of the micro-structure in 7A04 alloys.Some conclusions of the study are as follow:1.Comparing with a present heat treatment craft T6a-10（485℃/50min /water quench+100℃/36h/aging）craft,the appliance of new heat treatment crafts T6a- 17（485℃/50min/water quench+100℃/36h/aging）and T6a3-21（485℃/50min/ water quench +160℃/10min+120℃/10min+60℃/240h/aging）increased the toughness of 7A04 alloy more markedly with the premise of a little increasing or unmarkedly dropping of the alloy strength,α_k is increased by 25.1%and 54.5%,K_ICis increased by 20.8%and 29.4%.2.The corresponding connection among mechanical properties,impact toughness and fracture toughness of the alloy were assured.Especially,there existed close pertinence between impact toughness and fracture toughness.3.Comparing with precipitates of T6a-10 craft,T6a-17 crafts are smaller, which distributed more uniformly and dispersedly;The alloys treated by T6a-10 craft separated out precipitates of different sizes,the sizes of precipitates were altered in group.Accordingly,the impact toughness and fracture toughness of alloys were markedly improved.更多还原