Li Huiqu, Wang Liang, He Weiwei, Cheng Liqiang, Chen Junzhou, Yi Linna
AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China.
Beijing Engineering Research Center of Advanced Aluminum Alloys and Applications, Beijing 100095, China.
Materials (Basel). 2023 Jul 20;16(14):5129. doi: 10.3390/ma16145129.
Large-scale, high-strength aluminum alloy forgings are essential components in the aerospace industry, with benefits including increasing strength and decreasing weight. Accurate shape-property control is the secret to forging quality. This study uses the alloy 7050 to experimentally evaluate the parametric influence of cold compression on residual stress and mechanical characteristics. The evolutions of mechanical properties, microstructure and residual stress are theoretically studied using various cold compression strains from 1% to 5% on an equivalent part, of which the results are further applied on a complicated rib-structured die forging. It is demonstrated that increasing the compression strain reduces the tensile strength of the material, but has little impact on conductivity and fracture toughness. According to the TEM results, compression also encourages the precipitation and growth of precipitated phases, particularly in positions with high dislocation densities after aging. Cold compression significantly reduces residual stress; nevertheless, as compression strain increases, residual stress first decreases and then increases. With the use of rib-structured forging, it is observed that the compression strain for 7050 aluminum alloy ranges from 2% to 4%, and the combined pressing method of the rib and web improves the uniformity of residual stress.
大型、高强度铝合金锻件是航空航天工业中的关键部件，具有提高强度和减轻重量等优点。精确的形状-性能控制是锻造质量的关键。本研究使用7050合金通过实验评估冷压缩对残余应力和力学性能的参数影响。在等效部件上使用1%至5%的各种冷压缩应变，从理论上研究力学性能、微观结构和残余应力的演变，其结果进一步应用于复杂肋结构模锻件。结果表明，增加压缩应变会降低材料的抗拉强度，但对电导率和断裂韧性影响不大。根据透射电镜结果，压缩还促进析出相的析出和生长，特别是在时效后位错密度高的位置。冷压缩显著降低残余应力；然而，随着压缩应变增加，残余应力先减小后增大。通过肋结构锻造观察到，7050铝合金的压缩应变范围为2%至4%，肋和腹板的组合压制方法提高了残余应力的均匀性。
