| Abstract |
| A series of tensile tests were carried out on a B2-type b-CuZn alloy in the temperature range, room temperature to 400oC at three different strain rates (10^(-5) sec^(-1), 10^(-4) sec^(-1), 5.2x10^(-2) sec^(-1)). The stress-strain curves could be divided into three types. Type I indicates a remarkably linear sustained work hardening to fracture, type II work hardening and subsequent necking, type III yield drop behavior and stress saturation, respectively; corresponding to the insensitive yield stress region, anomalous yield stress region, and yield stress decreasing region, in the yield strength vs. temperature graph. The ultimate tensile strength basically decreased as temperature increased, only showing characterized strength hump-up region just below T_(p). The fracture mode was changed mainly from transgranular at room temperature to intergranular at high temperatures. The elongation increases with increasing temperature in region I, and then slightly decreases in region II (anomalous yield stress region). When the specimens were tensile-fractured at high temperatures (region III, above Tp), the elongation drastically increased with decreasing strain rate, for instance from 12% at 5.2x10^(-2) sec^(-1) to 87% at 10^(-5) sec^(-1). The dependence of ductility on strain rate was mainly attributed to the thermally activated <100> dislocation climb, inducing stress relief at the grain boundaries, as evidenced by microvoids at grain facets. |
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| Key Words |
| β-CuZn alloy, Tensile property, Fracture mode, Yield stress anomaly, Strain rate dependence, Temperature dependence |
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