Surface Structure Evolution and Abnormal Wear Behavior of the TiNiNb Alloy under Impact Load

Abstract

The TiNiNb alloy exhibits a linear increase in wear with a number of impacts at the low impact energy density E im of 1.6 J/cm 2 . However, a change in the volume wear occurs on the wear curve when E im is increased to 2.42 J/cm 2 . In this case, when the number of impacts N is more than 3 9 10 5 cycles, the wear rate decreases from 5.8 9 10 À6 to 1.9 9 10 À6 mm 3 /cycle, which is only one-half of that under low E im (1.6 J/cm 2 ). It is significant for practical applications because impact energy increases while the wear rate decreases. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses show that a large number of amorphous structures are produced on the sample surface at high E im , while no new crystalline phases appear. The abnormal wear behavior of the TiNiNb alloy can be attributed to the excellent wear behavior of amorphous structure and the consumption of impact energy during amorphous structure production.

Quasi-nano wear mechanism under repeated impact contact loading

“…It is interesting that for some higher strength materials (for example, the four materials in this study) at a relatively low impact energy the subsurface cracks could be found, while at the high impact energy density the cracks after turning could not. This has been confirmed by authors' experiments [21][22][23][24][25][26]. It can be only explained as follows.…”