Abstract

High strain rate rolling (HSRR) is developed to improve the strength, plasticity and stress corrosion resistance of 7050 aluminum alloy simultaneously. The volume fraction of the small-angle grain boundary in the HSRRed alloy sheet is 89.9%. TEM shows that the presence of dislocations and sub-grains promotes the precipitation of the second phase. The alloy in the T6 state has the highest strength (622 MPa) and the biggest elongation to rupture (20.6%), but poor corrosion resistance. The over-aged state shows the best corrosion resistance. The RRA state can achieve the tensile strength equivalent to T6 of 614 MPa, the highest yield strength of 561 MPa and corrosion resistance comparable to the over-aged state. TEM observation shows the existence of sub-grains and dislocations plays an important role in the nucleation of the second phase. The high strength can be attributed to the higher volume fraction of the precipitates, and the high plasticity can be attributed to the higher work hardening rate. The better corrosion resistance can be ascribe to the wider precipitate-free zones at the grain boundary and the presence of the larger size second phase particles.

Graphic Abstract

中文翻译：

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热处理对高应变速率轧制7050铝合金组织和性能的影响

摘要

开发高应变速率轧制（HSRR）是为了同时提高7050铝合金的强度，可塑性和抗应力腐蚀性能。HSRRed合金薄板中小角晶界的体积分数为89.9％。TEM显示，位错和亚晶粒的存在促进了第二相的沉淀。T6状态的合金具有最高的强度（622 MPa）和最大的断裂伸长率（20.6％），但耐腐蚀性差。过时状态显示出最佳的耐腐蚀性。RRA状态可实现相当于T6的抗拉强度614 MPa，最高屈服强度561 MPa，以及与过时状态相当的耐蚀性。TEM观察表明，亚晶粒和位错的存在在第二相的成核中起着重要作用。高强度可归因于沉淀物的较高体积分数，而高可塑性可归因于较高的加工硬化率。更好的耐腐蚀性可以归因于晶界处较宽的无沉淀区和较大尺寸的第二相颗粒的存在。

图形摘要