γ-TiAl合金铣削加工表面残余应力研究

为了探索高温理想结构材料γ-Ti Al合金铣削表面残余应力特性,结合正交试验数据处理方法中的极差分析法,建立各工艺因素情况下不同水平对表面残余应力的关系曲线,并对其工艺过程中的热力影响机理进行分析;同时建立面向残余应力的各因素灵敏度数学模型,进而确定以获取较大残余压应力为目标的工艺参数优选区间。研究表明:在试验参数限定范围内,步进方向以及进给方向均呈现为残余压应力,主要原因是冷塑性变形占主导作用。通过对灵敏度数学模型进行分析,发现残余应力对设计变量中的铣削速度变化最敏感,对每齿进给量、铣削深度和铣削宽度的敏感程度近似相同,为Ti Al金属间化合物铣削表面残余应力控制研究提供了理论依据。

Surface Residual Stress of Gamma Titanium Aluminide in Milling Process

In order to explore the influence law of milling parameters on residual stress induced in the process of milling ideal high-temperature structural material of gamma-TiA1 alloy,the extreme difference analysis method is used based on orthogonal experiment data processing.The relationships between different levels of process factors and residual stress are established,as well as the thermal-mechanical mechanisms are analyzed.At the same time,a sensitivity mathematical model of machining factors to residual stress is obtained,which determines the parameters optimization range to get larger residual compressive stress.Research shows that during the range of experimental parameters,the residual stresses along the direction of stepper and feed are all compressive caused by cold plasticity deformation mainly.With regard to cutting parameter sensitivity analysis,it has been found that the residual stress is most sensitive to the milling speed,as one of design variables,while nearly the same degree to feed per tooth,cutting depth and cutting width,which provides a theoretical basis to control surface residual stress in the milling process of titanium aluminium alloy.