Plastic flow of CuTi alloys at elevated temperatures

Copper-titanium alloys containing 0.1, 1.0. 2.5 and 5.6 percent wt. of titanium were tensile tested in the temperature range 25degreesC-700degreesC. Alloys of 1.0% to 5.6% titanium content, aged on the peak of hardness before the tensile test, exhibit plateau of the proof stress vs temperature of deformation between 25degreesC and 300degreesC. This result is comparable with that reported for precipitation hardened beryllium bronze tested at elevated temperatures. During straining of solution treated copper-titanium alloys, the dynamic strain ageing phenomenon occurs. Instability of the load (Portevin Le Chatelier effect), maximum of the proof stress vs temperature of deformation, decrease of the strain rate sensitivity together with transient of load on change of the crosshead speed and drastic decrease of total elongation of the specimens were observed. A considerable reduction of the total elongation of samples aged before the trensile test on the peak of hardness also takes place. Effects of dynamic strain ageing were more pronounced in alloys with higher concentration of titanium.