固溶温度对7050铝合金锻板组织和性能的影响

Effect of solid solution temperature on microstructure and properties of 7050 aluminum alloy forging plate

采用差热分析仪、光学显微镜、扫描电镜、X射线衍射仪和力学试验机研究了固溶处理对7050铝合金锻板组织和拉伸性能的影响。结果表明:变形态7050铝合金锻板中的第二相为含铁相(Al7Cu2Fe)、S相(Al2CuMg)和MgZn2相。MgZn2相能够在467℃到482℃温度区间回溶,当固溶温度达到482℃时,7050铝合金中的S相几乎全部溶入铝基体。单级固溶条件下,7050铝合金强度是沉淀强化和位错强化二者平衡的结果,呈现出先升高后降低的趋势,并在477℃时达到最大值。202℃低温保温处理促进7050铝合金发生回复,抑制再结晶,增大位错强化效果,其抗拉强度和屈服强度达到最大值,分别为559.5 MPa和500 MPa。

Effect of solid solution treatment on microstructure and tensile properties of 7050 aluminum alloy forging plate was studied by means of differential scanning calorimetry(DSC), optical microscope, scanning electron microscopy, X-ray diffractometer and mechanical testing machine. The results show that the second phases of the deformed 7050 aluminum alloy forging plate are iron-rich phase(Al7Cu2Fe), S phase(Al2CuMg) and MgZn2 phase. The MgZn2 phase can be dissolved in the temperature range from 467 ℃ to 482 ℃. When the solid solution temperature reaches 482 ℃, the S phase in the 7050 aluminum alloy almost all dissolves into the aluminum matrix. Under the condition of single stage solid solution, the strength of the 7050 aluminum alloy is the result of the equilibrium of precipitation strengthening and dislocation strengthening, shows the trend of first increasing and then decreasing, and reaches the maximum value at 477 ℃. The low temperature holding treatment at 202 ℃ promotes the recovery of the 7050 aluminum alloy, inhibits recrystallization and increases the dislocation strengthening effect, and its tensile strength and yield strength reaches the maximum value of 559.5 MPa and 500 MPa, respectively.