Study on Surface Micro-Texture of Ti2AlNb-based Alloy Cladding Layer by Ultrasonic and Temperature Field Assisted Milling

Abstract

Ti2AlNb-based alloy is difficult to machine due to its high thermal deformation resistance, significant work hardening and poor surface processing quality. In this paper, Ti2AlNb alloy cladding layer was prepared on Ti-6Al-4V substrate by laser cladding technology. Combined with ultrasonic vibration and temperature field assisted milling composite processing technology, the influence of ultrasonic amplitude and preheating temperature on the surface texture morphology of the alloy was investigated. The results show that ultrasonic vibration can change the material removal method, change the machined surface from ordinary parallel tool marks to regular periodic grid micro-texture, and significantly improve the surface texture regularity. Moderate preheating can improve the cutting stability through the thermal softening effect of the material, and effectively suppress the processing defects such as ploughing and tearing. As the preheating temperature increases from 30℃ to 200℃, the surface roughness continues to decrease, and the texture quality is gradually improved. Too high preheating temperature (300℃) will lead to excessive softening, sticking and thermal damage of the material, resulting in surface texture distortion and significant increase in roughness. Within the range of experimental parameters, 200℃ preheating coupled with 2μm ultrasonic amplitude can obtain the optimal surface morphology and processing quality.