Precipitation Hardening of Cu-3Ti-1Cd Alloy

Autor: R. Markandeya, S. Nagarjuna, D.S. Sarma
Rok vydání: 2007
Předmět:
Zdroj: Journal of Materials Engineering and Performance. 16:640-646
ISSN: 1544-1024
1059-9495
DOI: 10.1007/s11665-007-9082-7
Popis: Precipitation strengthening of Cu-3Ti-1Cd alloy has been studied using hardness and tensile tests, electrical resistivity measurements, and transmission electron microscopy. The alloy exhibited a hardness of 117 Hv in solution-treated (ST) condition and attained a peak hardness of 288 Hv after aging at 450 °C for 72 h. Electrical conductivity increased from 7%IACS (International Annealed Copper Standard) in ST condition to 13%IACS on aging at 450 °C for 16 h. The alloy exhibited yield strength (YS) of 643 MPa and ultimate tensile strength (UTS) of 785 MPa in peak-aged (PA) condition. Strengthening in Cu-3Ti-1Cd alloy in PA condition is attributed to solid solution strengthening effect of cadmium (Cd) as well as fine scale precipitation of metastable and coherent β′-Cu4Ti phase. On overaging at 450 or 500 °C, the alloy showed a decrease in hardness as a result of formation of equilibrium precipitate β-Cu3Ti as continuous precipitation within the matrix and as discontinuous precipitation at the grain boundaries. While the tensile properties are better, the electrical conductivity of Cu-3Ti-1Cd alloy is less than that of binary Cu-2.7Ti alloy. The strengthening mechanism is the same in both binary and ternary alloys of Cu-Ti, i.e., precipitation of metastable and coherent β′-Cu4Ti phase.
Databáze: OpenAIRE