挤压比对7N01铝合金应力腐蚀性能的影响

Effects of extrusion ratios on stress corrosion properties of 7N01 aluminium alloy

选取3种不同的挤压比10、22和35,研究了挤压比对7N01铝合金微观组织、力学性能以及应力腐蚀性能的影响规律。研究结果表明:随着挤压比的增加,合金的晶粒尺寸变小,挤压条带宽度变窄,合金的时效响应速度加快,合金的强度显著提升。同时,在挤压温升和冷却速度的双重作用下,随着挤压比的增大,合金中过饱和固溶原子的数量增加,晶界析出相的连续性发生改变,形成不连续-略连续(细小)-不连续(粗大)的变化过程,由此导致合金的应力腐蚀指数随着挤压比的增大呈现先增加后减小的趋势,因此在实际生产时,应避开挤压比为22以内的范围。

Three kinds of extrusion ratio of 10,22,35 were employed to investigate the effect of extrusion ratio on microstructure,me-chanical properties and stress corrosion properties.The results show that with the increase of extrusion ratio,the grain size of the alloy de-creases,the width of extrusion strip narrows,the aging response speed of the alloy increases,and the strength of the alloy increases signif-icantly.At the same time,under the co-effects of extrusion temperature rise and cooling rate,the number of supersaturated solid solution atoms increases,and the continuity of precipitated phases at grain boundaries changes from discontinuous,slightly continuous(fine)to discontinuous(coarse)with the increase of extrusion ratio,which results in stress corrosion index of the alloy showing a trends of increas-ing firstly and then decreasing.Therefore,the extrusion ratio of 22 or less should be avoided in industrial production.