Microstructure, Mechanical Properties, and Sliding Wear Behavior of Spark Plasma Sintered Ti-Cu Alloys

Abstract

Ti-Cu alloys have attracted significant interests for use in dental and orthopedic implants because of excellent antibacterial activity. However, limited research efforts have been devoted to their sliding wear behavior. Herein, we have fabricated nearly fully dense ultra-fine-grained Ti-Cu alloys with the Cu contents of 5 and 25 at. pct using a combination of high energy ball milling and spark plasma sintering (SPS) and systematically investigated their microstructure, mechanical properties, and sliding wear behavior. The results show that the Ti95Cu5 alloy consists of Ti2Cu precipitates uniformly distributed in an α-Ti matrix. This particular microstructure results in excellent mechanical properties, including a compressive yield strength of up to 1593 MPa, compressive strength of over 2400 MPa, and fracture strain of up to 26.8 pct. Conversely, the bulk Ti75Cu25 alloy consists mainly of Ti2Cu with a small amount of α-Ti and exhibited a slightly higher yield strength but reduced compressive strength and fracture strain. The hardness and yield strength of the Ti-Cu alloys were approximately three times and one order of magnitude higher, respectively, than those of commercially pure Ti. Sliding wear tests reveal that the wear mechanism of the ultra-fine-grained Ti-Cu alloys is distinct from that of CP-Ti and that the wear resistance is enhanced with increasing Ti2Cu content.