Influence of Ultrasonic Surface Rolling on Microstructure and Wear Behavior of Selective Laser Melted Ti-6Al-4V Alloy

Abstract

The present article studied the effect of ultrasonic surface rolling process (USRP) on the microstructure and wear behavior of a selective laser melted Ti-6Al-4V alloy. Surface characteristics were investigated using optical microscope, nano-indentation, scanning electron microscope, transmission electron microscope and laser scanning confocal microscope. Results indicated that the thickness of pore-free surfaces increased to 100~200 μm with the increasing ultrasonic surface rolling numbers. Severe work hardening occurred in the densified layer, resulting in the formation of refined grains, dislocation walls and deformation twins. After 1000 N 6 passes, about 15.5% and 14.1% increment in surficial Nano-hardness and Vickers-hardness was obtained, respectively. The hardness decreased gradually from the top surface to the substrate. Wear tests revealed that the friction coefficient declined from 0.74 (polished surface) to 0.64 (USRP treated surface) and the wear volume reduced from 0.205 mm−3 to 0.195 mm−3. The difference in wear volume between USRP treated and polished samples increased with sliding time. The enhanced wear resistance was concluded to be associated with the improvement of hardness and shear resistance and also the inhibition of delamination initiation.

A Comparative Study of Friction and Wear Processes of Model Metallic Biomaterials Including Registration of Friction-Induced Temperature Response of a Tribological Pair

“…Moreover, microcracked flakes are also present. According to the other authors, this type of surface damage is typical of a mixture of abrasive and adhesive wear [44]. Therefore, it can be concluded that scuffing occurred.…”

Experimental Investigation on Ultrasonic Atomization Assisted Turning of Titanium Alloy

“…Titanium alloy has a high strength-weight ratio, good corrosion resistance, outstanding mechanical and thermal properties, and is currently one of the most widely used materials in aerospace, shipbuilding, medical, and other fields [1][2][3][4][5]. However, titanium alloy still has some shortcomings, such as low thermal conductivity, high strength, and easy chemical reactivity with tool materials, which impairs the machinability of conventional machining and makes it a typical difficult-to-cut material [6][7][8][9][10]. Dry cutting is a commonly used method in the green manufacturing of titanium alloys.…”

Fabrication, Structure, and Mechanical and Ultrasonic Properties of Medical Ti6Al4V Alloys Part II: Relationship between Microstructure and Mechanical Properties and Ultrasonic Properties of Ultrasonic Scalpel

“…Especially in ultrasonic surgery, the Ti6Al4V alloy is widely used for ultrasonic scalpels, which require not only favorable biocompatibility, but also excellent mechanical and ultrasonic properties [2]. Most of the current investigations focus on the effect of ultrasonic processing on the wear and fatigue behavior of this Ti6Al4V alloy [3][4][5], as well as the effect of microstructures on the ultrasonic wave velocity and attenuation coefficient of Titanium alloys [6,7]. The influence of heat treatment on the mechanical properties of Ti6Al4V alloys have been described in detail in the first paper of a series of papers focusing on the fabrication, structure and mechanical and ultrasonic properties of medical Ti6Al4V alloys.…”