Fractured Surface Morphology and Mechanical Properties of Ni-Cr Based Alloys with Mo Content for Dental Applications

In this study, fractured surface morphology and mechanical properties of Ni-Cr-Mo alloys with various contents of Mo for dental material use have been evaluated by mechanical test. The alloys used were Ni-13Cr-xMo alloys with Mo contents of 4, 6, 8, and 10 wt.%, prepared by using a vacuum arc-melting furnace. Ni-13Cr-xMo alloys were used for mechanical test without heat treatment. The phase and microstructure of alloys using an X-ray diffraction (XRD) and optical microscopy (OM) were evaluated. To examine the mechanical properties of alloys according to microstructure changes, the tensile test and the hardness test were carried out using tensile tester. To understand the mechanism of Mo addition to Ni-Cr alloy on mechanical property, the morphology and fractured surfaces of alloys were investigated by field-emission scanning electron microscope (FE-SEM). As a result, 79Ni-13Cr-8Mo alloy was verified that the tensile strength and the hardness were better than others. Varying Mo content, the changes of microstructures of alloys were identified by OM and SEM and that of 79Ni-13Cr-8Mo alloy was proved fabricated well. Microstructures of alloys were changed depending on Mo content ratio. It has been observed that 8% alloy had the most suitable mechanical property for dental alloy.