Mischmetal as an alloying addition to amorphous materials and glass formers

Abstract

The present paper reports the results on full or partial replacement of Y and the rare-earth (RE) elements in Al–Y–Ni–Co, Mg–Ni–Y, Ge–Al–La and Ge–Cr–Al–RE rapidly solidified alloys by Mischmetal (Mm). The alloys studied were produced by the melt-spinning technique and examined by X-ray diffractometry and differential scanning calorimetry. Mechanical properties were also examined. Full replacement of Y/RE metals by Mm reduces the width of the supercooled liquid region in the Al and Mg-based glass formers and changes primary crystallization mechanism of Al-based metallic glass while partial replacement of Y by Mm in the Al 85Y 8Ni 5Co 2 metallic glass does not change its primary crystallization behavior and width of the supercooled liquid region. Mg–Ni–Mm metallic glasses show high mechanical strength of about 600 MPa which is however lower than that of the Mg–Ni–Y alloys. Al 85Ni 5Y 4Mm 4Co 2 metallic glass shows high tensile strength of 1120 MPa which is comparable with 1250 MPa obtained for Al 85Y 8Ni 5Co 2. Mm addition did not worsen glass formation in the Ge–Cr–Al–RE alloys. Ge 70Cr 16Al 10Mm 4 alloy contains the highest possible Ge content in the amorphous single phase so far obtained by rapid solidification.