Effect of tungsten content on glass forming ability and microhardness of Ni-Cr-B-W metallic glasses

Purpose: The thermal and mechanical properties of Ni-Cr-B-W alloys as a function of tungsten content were studied. Design/methodology/approach: The studies were performed on (Ni49.7Cr14.7B35.6)100-xWx(x:15-40) metallic glass in the form of foils, which have thickness of 20 and 100 μm. Structures of samples wer examined by X-ray diffraction (XRD). Thermal stabilities of the amorphous samples were measured using differential scanning calorimetry (DSC). Microhardness of the amorphous samples were determined by Vicker’s hardness tester. Findings: The XRD investigations revealed that samples of the alloys which have the thickness of 20 μm were amorphous. However, 100 μm samples of the alloys were not amorphous, but contained crystalline phases. Increasing the tungsten addition improved the glass transition and crystallization temperatures of the alloys. Also, microhardness of the alloys improved with tungsten addition. Practical implications: Thermal and mechanical properties of the alloys investigated depend on their tungsten content. Originality/value: This is the first study on Ni-Cr-B-W metallic glass system. Also, because of the production method used, all of the alloys were obtained as amorphous regardless of their composition, so their thermal and mechanical properties could be determined.