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在普通喷丸设备上增加增压罐,采用增压喷丸方法在7050铝合金表面制备出平均直径约为30 nm的纳米晶层。通过差示扫描量热法研究了纳米晶层的热流量随温度的变化,利用K issinger方程计算得到7050铝合金经表面纳米化后其晶粒长大激活能比未处理样品高26.6 kJ/mo。lX射线衍射分析结果表明随着退火温度的升高,B ragg峰宽化明显减少,Scherrer-W ilson公式估算得到的晶粒尺寸在180~220℃明显增大。同时,显微硬度测试结果表明在此温度区间硬度相应迅速下降。因此,认为7050铝合金表面纳米晶层的热稳定温度在200℃以下。
A pressurization tank was added to the ordinary shot peening equipment. A nanocrystalline layer with an average diameter of about 30 nm was prepared on 7050 aluminum alloy by pressurized peening. The heat flux of the nanocrystalline layer was investigated by differential scanning calorimetry (DSC). The K issinger equation was used to calculate the activation energy of grain growth of the 7050 aluminum alloy after surface nanocrystallization was 26.6 kJ / mol . l X-ray diffraction analysis results show that with the annealing temperature increases, B ragg peak broadening significantly reduced, Scherrer-W ilson formula estimated grain size significantly increased at 180 ~ 220 ℃. At the same time, the microhardness test results show that the hardness decreases rapidly correspondingly in this temperature range. Therefore, it is considered that the thermal stability temperature of nanocrystalline layer on 7050 aluminum alloy surface is below 200 ℃.