专稿_7075铝合金的微组织和力学性能由电弧添加剂制成

【作者】马广义、刘德华、师敬桉、王儒政、牛方勇、吴东江

大连理工大学精密特种加工教育部重点实验室

[摘要]   7xxx在铝合金电弧增材制造过程中，由于组织不均匀和元素偏析，成型样品性能较低。针对这一问题，电弧增材制造 7075 铝合金薄壁件固溶 手动及时热处理（T对比研究了热处理前后微组织和机械性能的变化。结果表明，7075铝合金沉积试样中的晶粒被网状共晶组织包围，Zn、Mg和Cu晶界富集元素，产生元素偏析。T6 态热处理后，大多数共晶组织溶解，元素分布不均匀性显著提高。热处理样品的抗拉强度和断裂伸长率从(279)增加.4 ± 5.3）MPa提高至（493.9 ± 10.2）MPa，断后伸长率为3.78 % ± 0.35%增加到 9.66 % ± 1.70%。T6 状态样品的拉伸断口表面密布韧窝，断裂方式为韧性断裂。

关键词：电弧增材制造（WAAM）；7075

铝合金；组织形状；机械性能；热处理；

DOI:10.16080/j.issn1671-833x.2022.01/02.014

基金项目:**自然科学基金()；中央高校基础科研业务费；（DUT21YG116）。

Microstructure and Mechanical Properties of 7075 Aluminum Alloy Prepared by Wire and Arc Additive Manufacturing

[ABSTRACT]  The mechanical properties of the 7xxx series aluminum alloy deposited specimens are low due to the uneven microstructure and element segregation in the process of wire and arc additive manufacturing (WAAM). In order to solve this problem, the 7075 aluminum alloy thin-walled specimens deposited by WAAM were subjected to solid solution artificial aging heat treatment (T6 state). The microstructure evolution and mechanical properties before and after heat treatment were investigated. The results showed that the grains in the as-deposited specimen were

surrounded by eutectics with network-like structure, and the elements of Zn, Mg and Cu were concentrated at the grain boundaries, resulting in the element segregation. After T6 heat treatment, most of the eutectics were dissolved. Moreover, the unevenness of the element distribution was significantly reduced. Compared with the as-deposited specimens, the tensile strength and elongation of T6 specimens were improved. The value of tensile strength increased from (279.4 ± 5.3)MPa to (493.9 ± 10.2)MPa, and the elongation increased from 3.78 %± 0.35% to 9.66% ± 1.70%. The tensile fracture surface of T6 specimen was densely covered with dimples. Therefore, the fracture mode was ductile fracture.

Keywords: Wire and arc additive manufacturing (WAAM); 7075 aluminum alloy; Microstructure morphology; Mechanical properties; Heat treatment

 

作者介绍

马广义

副教授主要研究激光 / 电弧多能场增材制造原理及技术、大型薄壁构件激光精密焊接技术及设备、难加工材料激光精密加工技术。

马广义 ， 刘德华 . 电弧75 铝合金的微组织和力学性能[J]. 航空制造技术 ， 2022， 65(1/2)–19.