Hot Micro-hardness testing of drop cast ingots of fully amorphous SAM 1651 (Fe48Mo14Cr_(15)Y_2C_(15)B_6) produced by Oak Ridge National Laboratory was performed in order to determine the behavior of this Fe- bulk metallic glass under a variety of different test conditions. The effects of changes in test temperature on the micro-hardness/strength were determined over the temperature range from room temperature to 620 deg C. Although high (e.g. > 12 GPa) microhardness was exhibited at room temperature, significant hardness reductions were exhibited near Tg. Identical tests were conducted on Alloy C-22 and AISI 316L Stainless Steel for comparison and revealed much lower micro-hardness/strength at room temperature but relatively small changes in micro-hardness from room temperature to 620 deg C. In addition, the effect of exposure time at elevated temperature on the evolution of micro-hardness/strength was also evaluated for selected temperatures between 25 deg C and 620 deg C. Longer term thermal exposures at 150 deg C and 275 deg C were also conducted, followed by x-ray diffraction in order to determine the effects of low temperature long-term thermal exposures on the evolution of any structure. Exposures up to 102 days at 150 deg C and 55 days at 275 deg C did not reveal any changes in XRD, indicating stability of the structure at least up to the number of days exposed to this point.
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