EROSION-WEAR BEHAVIOUR OF ADDITIVELY MANUFACTURED TI-6AL-4V

Abstract

Titanium alloy Ti-6Al-4V, is a bimodal alloy (α+β) which has excellent corrosion resistance, high strength-weight ratio and biocompatibility for which it is preferred in aerospace, biomedical, automotive, and other engineering applications. During such applications in aerospace, the impingement of foreign particles in the air as a carrier medium leads to the degradation of material which leads to catastrophic failure over the long run and causes loss of life and expensive equipment. To comprehend the effects of solid particle erosion, we must conduct experiments examining the factors contributing to erosion. The current study investigates the effects of microstructure evolution, impact velocity, impingement angle, and temperature on the erosion-wear rates of Ti-6Al-4V alloy. Air jet erosion tests were conducted on both wrought and additively manufactured Ti-6Al-4V samples under specific operating conditions. Erosion-wear characteristics were analysed using field emission scanning electron microscopy (FE-SEM) where the results indicated that higher erosion rates occurred at an impact velocity of 150 m/s and an impingement angle of 30°, forming deep elliptical craters. In contrast, the lowest erosion rate was observed at a 90° impingement angle, forming spherical craters. Erosion rates were higher at room temperature than at 300°C for both sample types. In additively manufactured samples, electron backscattered diffraction (EBSD) maps confirmed that plastic deformation at elevated temperatures like 300℃ and this resulted in lower erosion rates. Additionally, additively manufactured samples exhibited higher erosion rates compared to wrought samples, attributed to porosity defects and the formation of a heterogeneous oxide layer. The mechanical properties were characterized using a Vickers microhardness tester.