THE EFFECT OF HEATING RATE AND NEUTRON IRRADIATION ON THE SPECIFIC HEAT BEHAVIOR OF A Cu-16.8 AT. % Al AND A Cu-17.2 AT. % Ga SOLID SOLUTIONS
The effect of heating rate on the specific heat behavior of binary solid solutions of copper containing 16.8 at.% Al and 17.2 at.% Ga in the range 40--700 deg C was investigated. Also the effect of prior neutron irradiation on the specific heat behavior of the Cu--Al alloy was studied. The specific heats were measured with a dynamic adiabatic calorimeter. An anomalous behavior in the specific heat was observed in both solid solutions that is explained in a consistent manner based on the presence of short-range order. The initial slow cooling at approximately 1/2 deg C/min from above about 330 deg C leaves the alloys prior to reheating with short-range order present. Upon reheating the kinetics of disordering are such that disordering does not begin until about 200 deg C. The specific heat then shows an anomalous rise of about 7% then decreases slightly around 300 deg C. From about 300 to 700 deg C the heating rates employed (1/2-7 deg C/min) are low enough to allow instantaneous equilibrium to be established. The specific heats remain anomalously high at least to 700 deg C. The specific heat curves in the region from 200 to 300 deg C shift to higher temperatures with increased heating rate. Neutron irradiation at 100 deg C after slow cooling increased the amount of short-range order present and also introduced excess vacancies. The additional short-range order caused an increase in the specific heat curve as compared to just slow cooling, since more order is destroyed. Due mainly to the excess vacancies the anomalous behavior was observed at lower temperatures than for just slow cooling. (auth)
- Research Organization:
- Univ. of Tennessee, Knoxville
- NSA Number:
- NSA-18-002298
- OSTI ID:
- 4149516
- Journal Information:
- Acta Met., Vol. Vol: 11; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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