Grinding force prediction and surface integrity analysis of Ti-4822 alloy formed by laser-directed energy deposition

Ti-4822 TiAl alloy is a typical intermetallic compound with great potential applications in aeronautics and astronautics and is widely available to high-pressure compressors and low-pressure turbine blades of aero-engines. Laser-directed energy deposition (LDED) is appropriate to form the Ti-4822 parts with complex shapes and structures. However, the LDED Ti-4822 alloy is a typical hard-brittle and difficult machining material with a poor rough surface and thermal conductivity, leading to poor grinding surface integrity. Therefore, in order to investigate and improve the grinding performance of LDED Ti-4822 alloy, a new prediction model of grinding force was proposed based on the combination of single-grain grinding and dynamic active grains grinding simulation. The influence of grinding parameters and grinding wheel category on grinding force, grinding force ratio, grinding surface morphology, grinding debris, and microhardness of LDED Ti-4822 alloy was analyzed by the single-factor and orthogonal experiments. The experimental results demonstrated that low feed speed, small grinding depth, and high grinding speed are beneficial to reduce grinding force and surface roughness (minimum 0.19 & mu;m). Compared with the CBN wheel, the diamond wheel is more appropriate for grinding LDED Ti-4822 alloy because of a smoother grinding surface with less defects and lower wheel wear. Significant surface hardening will be generated by grinding LDED Ti-4822 alloy. The maximum Vickers hardness can reach 776.6 HV, and the mean depth of grinding hardened layer is 20 & mu;m.