强塑性变形与微量元素协同调控Al-Cu-Mg-×(×=Zr、Er、Sc)合金微观结构、高温力学行为及其耐热机理研究

2524 aluminum alloy is a key material for aircraft envelope due to its excellent thermal stability under a relatively high temperature. However, how to furtherly improve its mechanical properties at both room temperature and high temperature becomes one of the focus, and the heat-resistance mechanism should be further investigated. Thus, the present investigations will prepare ultrafine grained Al-Cu-Mg-× alloy sheet by a novel large strain rolling, and center on the problems of uniform shear law of Al-Cu-Mg-× alloy based on microstructure control fabricated ba large strain rolling, and the relationship between these microstructures and mechanical properties. Several important sites will be investigated, such as, we will obtain the uniform shear law and deformation permeability and evolution mechanism of microstructures and texture for Al-Cu-Mg-× alloy during large strain rolling, the response of microstructures on temperature, and the the effects of microstructures on room and thermal mechanical properties under complex conditions. I believe it can provide more references on summarizing the deformation mechanism of large strain rolling and reveal the relationship between grain boundary, precipitation, texture and thermal mechanical behavior. We can also prepare Al-Cu-Mg-× alloy sheet with high strength and toughness. The present investigation is an attractively exploration to fabricate aluminum alloy with excellent mechanical properties.

2524耐热铝合金是新一代飞机蒙皮材料，但其室温与高温性能有待进一步提高，对其耐热机理尚需深入研究。本项目采用自主发明的大应变轧制方法制备高强高韧Al-Cu-Mg-×耐热铝合金板材，针对“基于微观结构控制的Al-Cu-Mg-×合金大应变轧制均匀剪切变形规律、小角度晶界、织构等亚结构与Al-Cu-Mg-×合金力学行为的关系”等科学问题，通过对Al-Cu-Mg-×合金大应变轧制均匀剪切规律及变形渗透性、大应变轧制Al-Cu-Mg-×合金微观结构与形变织构演变机制，Al-Cu-Mg-×合金微观结构对热场的响应行为、多场服役条件下微观组织与高温力学行为耦合机制等4个方面开展研究，揭示晶界、第二相、织构等微观结构特征对Al-Cu-Mg-×合金高温力学行为的影响机理，制备出高强高韧、耐热性好的Al-Cu-Mg-×合金板材，此项研究是铝合金轧制变形技术中的一项新探索，具有重要的实际意义。

本项目针对飞机蒙皮用耐热铝合金高温力学性能亟需提高，以满足国家大飞机项目对高强、高韧、热稳定性优异的耐热铝合金的重大需求这一背景，以飞机蒙皮用2524耐热铝合金为原型，通过添加微量Zr、Er、Sc以及Cu等合金元素调整其成分，确立了其均匀化处理、固溶、时效等热处理制度。采用自主发明的大应变轧制技术进行塑性变形，研究了变形工艺参数、剪切变形规律、微观结构之间的关系，获得了大应变轧制变形工艺与Zr、Er、Sc、Cu等合金化元素对Al-Cu-Mg-×合金超细晶组织形成与演变规律的影响机制，当Zr含量为0.5wt %时，其抗拉强度、屈服强度、断后伸长率分别为645 MPa、548 MPa、11 %；当Er含量为0.1wt %时，其抗拉强度、屈服强度、断后伸长率分别为638 MPa、542.3 MPa、9.6 %；Sc含量为0.1wt %时， 其抗拉强度、屈服强度、断后伸长率分别为623 MPa、529.6 MPa、9.6 %。研究了Al-Cu-Mg-Sc合金的各向异性特性，结果表明，0°方向具有更佳的力学性能。在 σ =190 MPa、t =100 h条件下对WA(未时效态)、UA(欠时效态)、PA(峰时效态)、OA(过时效态)合金进行了蠕变持久试验，探究了合金蠕变机理。本项目研究工作对拓展Al-Cu-Mg-×合金塑性成形理论与成形机制具有重要的实际意义。

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