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采用差示扫描量热法(DSC)、高温X射线衍射(HTXRD)、透射电镜(TEM)观察、硬度测试以及电导率测试等手段,研究了不同的加热速率(340,57,4.3℃·min-1)对7050铝合金在回归加热过程中组织演变的影响。结果表明:在回归加热过程中,预时效态组织的GP区和η′相将发生回溶或依次转变为η′相和η相,而且回归加热速率对回溶和转变的温度产生显著影响,随加热速率提高,回溶和转变的温度升高。在一定的回归温度下,不同的加热速率使得合金在加热至回归温度时较预时效态具有不同的组织结构,从而影响合金在回归阶段发生不同的组织转变。本研究认为中等加热速率下,预时效态组织在加热至回归温度时所获得的组织结构最有利于回归阶段的组织转变。
The effects of different heating rates (340, 57 and 4.3 ℃ · min) were studied by differential scanning calorimetry (DSC), high temperature X-ray diffraction (XRD), transmission electron microscopy (TEM), hardness test and conductivity test. -1) on the microstructure evolution of 7050 aluminum alloy during reheating. The results show that the GP and η ’phases of the pre-aged structure will be dissolved or turn into η’ phase and η phase in the process of reheating, and the regression heating rate has a significant effect on the temperature of the solution and transition. As the heating rate increases, the temperature of the solution and transition increases. At certain regression temperature, the different heating rates make the alloy have different microstructures when compared with the pre-aging state when heated to the regression temperature, which will affect the different transformation of the alloy during the regression. In this study, the tissue structure obtained from the pre-aging microstructure at heating to the regression temperature is most conducive to the microstructure transition during the regression stage at medium heating rate.