Effects of Tungsten and Boron Contents on Crystallization Temperature and Microhardness of Tungsten Based Metallic Glasses

Abstract

Effects of tungsten and boron contents on the thermal properties and microhardness of W–Fe–B metallic glass system were studied. Thin foils, with thicknesses of 20 and 100 μm, of the alloys were produced by piston and anvil method in an arc furnace. The structures of the foils were investigated by X-ray diffraction. Thermal stabilities of the alloys were examined by using differential scanning calorimetry. 20-μm- thick foils of all the alloys were determined to be fully amorphous, but crystalline phases were detected in the 100-μm-thick foils. It was found that crystallization temperatures of the alloys are between 1060 and 1177 K. Tungsten and boron content increases improve the crystallization temperature and microhardness of the alloys significantly, but deteriorate the glass forming ability of the alloys. It was also observed that for constant Fe content, increasing tungsten content to the level higher than that of boron content does not result in any further improvement in crystallization temperature, but improves glass forming ability significantly. The alloy containing highest total amount of tungsten and boron, W35Fe35B30, has the highest crystallization temperature, 1177 K, and microhardness, 1634 HV.