Synthesis and high mechanical strength of Al-based alloys consisting mainly of nanogranular amorphous particles

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 1996-10, Vol.217 (1-2), p.401-406
• Main Authors: Inoue, A., Kimura, H.M., Sasamori, K., Masumoto, T.
• Format: Article
• Language: English
• Subjects: Mechanical strength; Nanophase materials; Synthesis
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/S0921-5093(96)10282-3

A new nonequilibrium structure consisting of nanogranular amorphous and fcc-Al phases was found to form in the rapidly solidified Al 94V 4M 2 (M = Fe or Co) alloys. The deviation from the Al-V-M components causes the formation of the nanoscale mixed structure of Al plus icosahedral (I) phases. The sizes of the amorphous and Al phase regions are about 10 nm and 7 nm, respectively, for the Al-V-Fe alloy and about 25 nm and 20 nm, respectively, for the Al-V-Co alloy. The formation of the nanogranular amorphous phase in coexistence with the Al phase is presumably owing to the suppression of the transition from the supercooled liquid to the I phase. The tensile fracture strength (σ f) reaches as high as 1390 MPa for the Al 94V 4Fe 2 alloy and 1250 MPa for the Al 94V 4Co 2 alloy and decreases significantly by the transition of I + Al phases. The high σ f is presumed to result from the formation of the nanoscale mixed structure consisting of amorphous + Al phases. The first success of fabricating the nanogranular amorphous phase is particularly important for the future development of nanophase materials.