Improved strengthening in supersaturated Al-Sc-Zr alloy via melt-spinning and extrusion

A supersaturated ternary alloy with concentration of Al-0.5Sc-0.4Zr at. % was produced utilizing melt-spinning. The melt-spun ribbon was consolidated and extruded into a rod. A two-step heat treatment was designed to age supersaturated alloys to peak hardness. The melt-spun ribbon and extruded rod were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), microhardness and tensile strength measurements. The ambient microhardness of two-step aged meltspun ribbon and extruded rod were 1120 MPa and 1180 MPa respectively. The yield and ultimate tensile strength of extruded rod were 300 and 315 MPa with 5.3% elongation. Larger precipitation volume fractions were found in two-step aged extruded rod than in melt-spun ribbon within shorter second-step aging. Strength levels in the melt-spun ribbon and extruded rod agree with order and Orowan strengthening predictions when using TEM measured precipitate radius and volume fractions. (C) 2020 Elsevier B.V. All rights reserved.