Mechanical properties and micro structural analysis of a NiCr alloy cast under different temperatures

The purpose of this study was to evaluate the chemical and metallurgical aspects, mechanical properties and hardness of the NiCr dental alloy when it was submitted to different castings temperatures. An NiCr alloy was cast, with lost wax technique, 20 specimens, separated in two groups of 10 each one, in two different casting temperatures: a) in accordance with the manufactures´ instructions (T1); b) above manufactures´ instructions (T2). It was done chemical and metallographic analysis witch scanning electron microscope in the alloy in these conditions: no cast, T1 and T2. It was determined mechanical properties and hardness, too. The microstructures were similar to no cast, T1 and T2. There was no significant difference between chemical analysis and to mechanical properties. The hardness of the T1 and T2 groups was greater than no cast group. Clinically, it may predict that when elevated temperatures were used, above manufacture´s recommendations (more than 100ºC), there will be failures in the prosthesis, like porosities, fissures or cracks.