Research On Grinding Of TC4-DT Titanium Alloy And Its Surface Properties

The new damage tolerance TC4-DT titanium alloy has a wide application prospect in aviationand astronautics industries due to its outstanding performance. However, TC4-DT is a typicaldifficult-to-grind aviation material because its surface can be easily damaged during the grindingprocess. In this thesis, the grinding and surface properties of TC4-DT were investigated by the methodof combining theoretic analysis, numerical simulation and experimental study.The main work and results are as follows:1. A three-dimensional finite element model of the transient grinding temperature field was builtbased on the uniform and triangular moving heat source models, and the grinding temperature wasinvestigated by simulation. It is found that simulation results are consistent with the experimentalresults. The influence rules of grinding parameters on grinding force and grinding temperature wasinvestigated through the experiments and the corresponding mathematical models were established.2. The influence laws of the grinding parameters on the surface roughness, surface morphology,microstructure and microhardness was studied through the grinding experiments. The results showthat good quality grinding surface of TC4-DT can be obtained using reasonable grinding parameters.The roughness of grinding surface is least and no grinding burns occur on the surface under the lowspeed condition of vs=25m/s, vw=12m/min and ap=10μm. Under the high speed condition of vs=80m/s,vw=1.4m/min and ap=10μm, the roughness of grinding surface is least and no grinding burns occur aswell.3. Based on the characteristics of the grinding surface, the dry friction and wear properties oftypical low and high speed grinding surfaces were studied. The results show that the hardness andfriction coefficient of low speed grinding surface decrease slightly. The friction coefficient of highspeed grinding surface that has no grinding burns, declined by over40percent compared with initialsurface of TC4-DT. Due to the existence of micro cracks and Ti compounds, the friction coefficient ofhigh speed grinding surface fluctuates in0.18~0.22. The dry wear mechanisms of grinding surface areadhesive abrasion, abrasive grain abrasion and delamination abrasion.