Abstract: The orthogonal tests of two dimensional ultrasonic rolling 7050 aluminum alloys were carried out. The surface roughness， surface hardness and residual stress were selected as the evaluation index of surface integrity. Gray correlation analysis method was used to evaluate the surface integrity. To obtain the optimal process parameters and corresponding evaluation index values， the prediction models for the evaluation index and the grey relational degree were constructed using multiple linear regression method along with studying the effects of process parameters on the surface roughness， surface hardness and surface residual stress. The results indicate that the contribution rates of process parameters are different with different evaluation indexes. The prediction models are significant at 95% confidence level， so they may be used to predict the test results accurately. The results of surface integrity obtained from the models are better than the optimal results selected from grey relational degree. The optimal process parameters obtained by the nonlinear programming solver based on the model are as follows. When the static force is as 327 N， the speed is as 400 r/min and the feed-rate is as 0.11 mm/r， the optimal surface integrity may be obtained with the residual stress -236.98 MPa， the surface roughness Ra 0.56 μm and the microhardness 695 HL.

Key words: two dimensional ultrasonic rolling, grey relational analysis, surface integrity, 7050 aluminum alloy

摘要： 采用正交试验法对7050铝合金进行二维超声滚压加工试验，选取表面粗糙度、表层硬度和残余应力作为表面完整性评价指标，运用灰色关联分析法对表面完整性进行综合评价。通过研究工艺参数对表面粗糙度、表层硬度和表面残余应力的影响，采用多元线性回归方法构建表面完整性各评价指标和灰色关联度预测模型，从而获取最优工艺参数和相应评价指标值。研究结果表明：对于不同的评价指标，各工艺参数的贡献率不同；预测模型在95%置信水平上均通过了显著性检验，可对试验结果进行准确预测；基于预测模型的规划求解所获得的表面完整性结果优于灰色关联度的优选结果，规划求解所获得的最优工艺参数为静压力327 N、转速400 r/min、进给量0.11 mm/r，此时残余应力σ值约为-236.98 MPa，表面粗糙度Ra值约为0.56 μm，表层硬度约为695 HL。

关键词: 二维超声滚压, 灰色关联分析, 表面完整性, 7050铝合金