2019 Pittsburgh AISTech

Effect of Solution Treatment on Grain Size and Toughness of Lightweight Fe-Mn-Al-C Steel (Room 412)

06 May 19
10:00 AM - 10:30 AM

Tracks: Metallurgy - Processing, Products & Applications

Speaker(s): Daniel Field, U.S. Army Research Laboratory; Krista Limmer, DEVCOM Army Research Laboratory, U.S. Army Research Laboratory

An age-hardenable Fe-Mn-Al-C steel was heat treated and impact toughness tested using Charpy V-notch testing at room temperature. The solutionizing temperature was varied from 1650 °F to 1960 °F (900 °C to 1075 °C) to obtain a range of grain sizes from 30 to 320 μm. After aging at 931 °F (500 °C) for varying times, and testing both hardness and toughness, it was found that lower solution treatment temperatures yielded higher toughness for an equivalent hardness. The improvement in toughness was noted to be primarily from the reduced grain growth associated with a lower solution treatment temperature. Fracture features of the alloy transitioned from ductile rupture at the low hardness/high toughness condition to an intermediate transgranular fracture; and at the highest hardness levels fracture morphology transitioned to intergranular failure due to κ-carbides precipitating on grain boundaries.