High Glass-Forming Ability and Unusual Deformation Behavior of New Zr-Cu-Fe-AI Bulk Metallic Glasses

摘要

A new series of bulk metallic glasses were developed by addition of Fe into the ternary Zr_(60)Cu_(30)Al_(10) alloy. Although Fe-Cu element pair shows distinct immiscibility with a large positive heat of mixing, substitution of Fe for Cu significantly improves the glass-forming ability of the ternary Zr_(60)Cu_(30)Al_(10) alloy. The critical diameter for glass-formation increases from 8 mm for Zr_(60)Cu_(30)Al_(10) alloy to 20 mm for Zr_(60)Cu_(25)Fe_5Al_(10) and Zr_(62.5)sGu_(22.5)Fe_5Al_(10) alloys. As compared with the ternary Zr_(60)Cu_(30)Al_(10) alloy, the new quaternary Zr-Cu-Fe-AI alloys show lower liquidus temperatures. The Zr_(60)Cu_(25)Fe_5Al_(10) and Zr_(62.5)Cu_(22.5)Fe_5Al_(10) alloys, the best BMG-formers in this alloy system, are found to locate very near a Zr-Cu-Fe-AI eutectic point. The new Zr-Fe-Cu-Al bulk metallic glasses exhibit high strength of about 1700 MPa. The plastic strain increases from 7.8% to 11.3% with increasing the content of Fe from 0 to 12.5%. The finding of a Ni-free Zr-based bulk glassy alloy with the extremely high glass-forming ability is expected to extend the future application of bulk metallic glasses.