β-brass critical temperatures and exponents as a function of composition

The specific-heat curves of $\beta$-brass for 45.1, 46.1, 47.8, and 49.1 at.% Zn have been determined using the ac method. The data were analyzed using linear and nonlinear least-square analyses by fitting to a typical specific-heat function. Ising values were compared with our derived values of the specific-heat critical exponents ${\alpha }^{\prime }$ and $\alpha$ and the ratio of the amplitudes $\frac{A^{\prime }}{A}$; also, our experimental values of the critical temperatures are compared with theory and with those of other workers. We have found that the critical exponent ${\alpha }^{\prime }(T<\mathrm{}{T}_c)$ is near zero and the exponent $\alpha (T>\mathrm{}{T}_c)$ is close to 1/8 for all compositions. Within the limits of error, we believe that there is a line of critical points over the $\beta$-brass range of composition.