Microstructure and mechanical properties of metastable fcc phase wires in Mn-Al-C system manufactured by in-rotating-water spinning method

Abstract

Metastable fcc phase with highly ductile nature has been found in melt-quenched Mn-Al-C alloys instead of extremely brittle equilibrium phases. This formation range is limited to about 9 to 22 at. pct Al and about 3.0 to 6.5 at. pct C. Further, the fee phase wires with circular cross section have been manufactured by an in-rotating-water spinning method. The wire diameter is in the range of 70 to 150 μm diameter and the average grain size is about 3 μm. The Vickers hardness, yield strength, and tensile strength of the wires increase with aluminum and carbon content and reach about 285 DPN, 560 MPa, and 960 MPa, respectively, for Mn74.5Al20.5C5-Elongation increases with decrease in aluminum and carbon, and the highest value is about 28 pct for Mn-13.5 pct Al-4 pct C alloy. The cold-drawing to about 60 pct reduction in area results in a very significant increase of tensile strength from 260 to 1460 MPa, through a remarkable work-hardening effect. Thus, the use of the in-rotating-water spinning method, being a new type of rapid quenching technique, is very useful to endow the manganese-base alloy wires exhibiting high strength combined with good ductility.