New Mg-based amorphous alloys with high strength and good ductility were produced in the Mg-Ce-Ni system by melt spinning. The tensile fracture strength ( σf) and Vickers hardness reach 750 MPa and 199 DPN for Mg80Ce10Ni10. The specific strength defined by the ratio of σf to density is as high as 27, being considerably higher than the highest value (≃20) for conventional Al-based alloys. The high-strength Mg-base amorphous alloys are expected to attract much attention as a new type of high-strength material with low density.
New Al-based amorphous alloys with high strength and good ductility were produced in an Al-Y-Ni system by liquid quenching. The tensile fracture strength ( σf) and Vickers hardness reach 1140 MPa and 300 DPN for Al87Y8Ni5. The specific strength defined by the ratio of σf to density is as high as 38, being much higher than that for conventional alloy steels. The high-strength Al-base amorphous alloys are expected to attract strong attention as a new type of high-strength material with low density.
New aluminum-based amorphous alloys were found to be formed in Al-Y-M and Al-La-M (M=Fe, Co, Ni or Cu) ternary systems by melt spinning. Their compositional ranges are 3 to 33 at%M and 3 to 22 at%Y or 2 to 18 at%La. The alloys containing more than about 80 at%Al have good bend ductility. The crystallization temperature T
x
increases from 414 to 831 K with an increase of M and yttrium or lanthanum contents. The effect of the solute elements on T
x
is interpreted to be dominated by the attractive interaction between aluminum and M, yttrium or lanthanum atoms.
New amorphous alloys in Al-M (M=Y, La or Ce) binary systems have been formed in the compositional ranges of 9 to 13 at% Y and 7 to 10 at% La or Ce by liquid quenching. Crystallization temperature, Vickers hardness and electrical resistivity at 293 K of the binary amorphous alloys increase with an increase of Y, La or Ce content from 437 to 516 K, 116 to 216 DPN and 54 to 93 µΩcm, respectively. The first amorphization for the Al-M binary alloys is important for subsequent development of Al-based amorphous alloys with high specific strength.
Ductile Al-Y-Ni and Al-Ce-Ni amorphous alloys were found to exhibit a glass transition at temperatures just below crystallization temperature. The glass transition temperature increases from 490 to 582 K with increasing solute concentration. The difference in specific heat between amorphous solid (AS) and supercooled liquid (SL) reaches 9.2 J/mol-K and the temperature coefficient of expansion and viscosity of the supercooled liquid are 100×10-5 K-1 and 3×1013 poise. By the transition of AS to SL, the Young's modulus and tensile strength also decrease steeply by about 63 and 66%, accompanied with an increase of elongation by about 320%.
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