Preliminary understanding of early-stage damage caused in high density solid particle erosion in particle accelerator piping applications

For future particle accelerator designs, granular target media are being considered to increase subatomic particle yield. Tungsten particles are of particular interest, but erosive wear has been identified as a key engineering issue. This work assessed the early-stage surface response of different surfaces to impingement by a tungsten erodent. Tests were conducted to compare the performance of three potential target container materials at different impingement angles: stainless steel 316, titanium grade 5 (Ti-6Al-4V), and Inconel 718. Particle velocity in the erosion test-rig was within the design range for a granular target. Impingement angles between 10° and 60° were used. 300 g of tungsten was applied at approximately 20 g/s to ensure that initial wear features could be analysed. Roughness was used to assess surface response to particle impacts, and statistical measures of fit were used to suggest dominant surface properties. The surfaces were measured using an optical profilometer, and inspected using SEM. It was found that roughness reached a maximum between impact angles of 30° and 45° for all materials. Stainless steel 316 and Ti-6Al-4V surfaces were roughened similarly, while Inconel 718 was consistently less roughened showing it may have the best potential, but longer-term wear tests are required to verify this.