Analysis of Phases and Their Role in Strengthening of Cu-Cr-Zr-Ti Alloy

In the present investigation, mechanical properties and microstructure of the Cu-Cr-Zr-Ti alloy were characterized by tensile testing, hardness measurement, and transmission electron microscopy (TEM) in different heat treatment conditions. TEM studies confirmed the presence of four phases in the solution-treated condition namely: copper matrix, spherical chromium-rich, TiS2, and ZrS2 particles. Aging in the temperature range of 400-600 degrees C has led to significant change in strength. Samples aged at 500 degrees C for 2 h showed maximum ultimate tensile strength and yield strength of 330 and 212 MPa, respectively, with ductility of 23%. The phase responsible for high strength after aging at 500 degrees C was identified as fine bcc chromium precipitates with average size of 3.0 perpendicular to 1.0 nm.