Effects of Ti Addition on Microstructure and Mechanical Properties of Extruded Cu40Zn-2.2Bi Brass by Powder Metallurgy

The effect of Ti addition on mechanical properties and microstructure of BS40-2.2Bi (Cu40Zn2.2Bi) brass was studied with respect to different contents of Ti addition. BS40 (Cu40Zn) and BS40-2.2Bi brass powders were prepared by a water atomization process. The BS40-2.2Bi powder and Ti powder were elementally mixed to prepare BS40-2.2Bi+xTi (x=0.3, 0.5 and 1.0 wt.%) premixed powders. The alloy powders and premixed powders were solidified at 1053K for 600 s by spark plasma sintering (SPS) and extruded subsequently. It was observed that a Ti2Bi intermetallic compound (IMC) was formed via the reaction between additive Ti and Bi alloy element, and the ductility of extruded BS40-2.2Bi+xTi was improved significantly. The yield strength and ultimate tensile strength were increased by increasing the contents of Ti addition. The optimal content of Ti addition was 0.3 wt.%, which served excellent mechanical properties and machinability comparing with BS40-2.2Bi. For example, it had yield strength of 235 MPa, ultimate tensile strength of 459 MPa and elongation of 39%, which showed 4.9%, 4.1% and 18% higher than that of extruded BS40-2.2Bi brass, respectively.