Surface Roughness of Electron Beam Melting TI-6AL-4V Effect on Ultrasonic Testing

Abstract

Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are known to have high surface roughness in as-manufactured condition, and surface roughness is known to affect the results of ultrasonic inspections. The experimental data from this research demonstrates the ability of ultrasonic inspections to identify flaws as small as 0.51 mm at 2.25 MHz, 5 MHz and 10 MHz through a machined surface. A frequency of 10 MHz provides better results than 2.25 MHz and 5 MHz through an as manufactured surface, where the highest natural surface roughness is present