Study Of Surface Integrity In High Speed Milling Of Titanium Alloy With PCD Tool

Titanium alloy are widely used in aeronautics and aerospace industry, and other civil applicationsas well owing to its excellent physical and mechanical properties, but it is also recognized as adifficult-to-machine material. How to improve its machining efficiency and its surface quality is urgentto solve. Compared with the commonly used carbide tools, PCD tools is of excellent properties such ashigh hardness, low thermal expansion coefficient and good thermal conductivity which are expected tobe able to improve tool life and surface quality. In this paper, some researches were carried out on thefundamental aspects of high speed milling of titanium alloys with PCD tool, such as surface roughness,hardening and residual stress. The major research work is as follows:1. Research of surface roughness in high speed milling of titanium alloys with PCD toolIn lower speed range, surface roughness in milling of titanium alloy is compared with PCD,coating and carbide tools. By using the regression orthogonal design, a mathematical model on therelationship between cutting parameters and surface roughness is established. The variance analysisvalidates the model. Influence of tool materials, milling parameters and tool wear on surface roughnessis also studied by using single factor design.2. Research of surface hardening and metallurgical microstructure in high speed milling oftitanium alloys with PCD toolDistribution of micro-hardness along the depth direction was measured to study the influence ofparameters and tool wear on surface hardening. And their influence on metallurgical microstructure isalso studied by metallographic observation.3. Research of surface residual stress in high speed milling of titanium alloys with PCD toolInfluence of milling parameter on surface residual stress is studied with x-ray method and based onthe orthogonal finite element model, this paper discuss the influence of cutting speed, tool geometryparameters and tool wear on residual stress. Distribution of residual stress along the depth direction isalso concerned.