Specific heat of the order-disorder transition in beta-brass and its relation to the Ising Model

Abstract

The specific heat Cp of beta-brass near its order-disorder transition has been measured with very high resolution. An ac calorimetry technique was used to make these measurements on ~-brass samples of varying composition. Cv Was then determined from Cp by use of the Pippard relations. The similarity between Cv and various Ising model calculations was found to be quite remarkable. Thus, the possible presence of relatively long-range pairwise interactions has no appreciable effect on the critical behavior of beta-brass's specific heat. The Cv results provide no verification of the "scaling-law" prediction a = a'. However, the Cp data do suggest the possibility of a' assuming its true critical behavior only ~ close to the critical temperature Tc. This could then explain why the a = a' equality has been so difficult to confirm experimentally.