Effect of Boron Addition on Thermal and Mechanical Properties of Cast ZA 12 Alloy

Abstract

In this study, the effects of boron (B) on microstructure, mechanical properties (hardness, tensile properties and corrosion resistance,) and thermophysical properties of ZA 12 alloy were investigated. The alloys were produced under a controlled atmosphere by a gravity casting process. Optical, scanning electron microscopy and X-ray spectrometry were used to determine the microstructural properties of the produced alloys. Further, hardness and tensile tests were carried out in the examination of the mechanical properties of the alloys. In addition, corrosion tests were performed on the alloys and the change of corrosion resistance with the addition of boron was defined. Finally, the effect of boron addition to ZA 12 alloy on its thermal properties was specified by hot disk thermal constants analyzer. The results showed that the addition of boron modified the microstructures of ZA 12 alloy. It was also observed that the hardness, ultimate tensile strength (UTS), and elongation of ZA 12 alloy increased with boron addition. The tensile fracture surfaces of ZA 12 alloy showed a clear brittle fracture nature, while finer dimple and fewer brittle cleavage surfaces were observed in the alloys with boron addition. Moreover, ZA 12 alloy's corrosion resistance was also increased with boron addition. The thermal conductivity of ZA 12 alloy was 124,928 W/(m K) and this value decreased after the addition of boron. Thermal diffusivity of the modified alloys was found to decrease after the thermal test, whereas the specific heat capacity of the samples increased.