19 - Optimization of heat treatments for a LP – DED Maraging 18Ni300 steel to improve mechanical properties.
Abstract
Maraging 18Ni300 steel is widely used in industry for its high mechanical properties and very good welding capabilities. It is an alloy of choice for additive manufacturing by Laser Powder Directed Energy Deposition (LP-DED). However, additive manufacturing processes result in specific non-equilibrium microstructures that may alter the response of the material to heat treatment and thus affect the mechanical properties. Indeed, conventional heat treatments of austenitization (820°C – 1 h) and aging (480°C – 4 h) do not make it possible to obtain mechanical properties close to those of the forged material. In this study, we analyzed the impact of aging of LP-DED 18NI300 on mechanical properties in order to increase its ductility while preserving its mechanical strength. First, differential thermal analysis (DTA) has been carried out to determine a temperature range of interest for the aging heat treatment. According to the literature, the precipitation hardening takes place between 485°C and 775°C. Several time-temperature conditions have been analyzed in this temperature range. The follow up of micro-hardness highlight different ageing kinetics. A change of ageing behavior is observed around 530°C. This phenomenon relates to the microstructure evolution involving two different mechanism, namely intermetallic precipitation in the one hand and the formation of reversed austenite in the other hand. SEM and TEM are carried out on different ageing conditions to better understand the hardness response. Furthermore, room temperature tensile tests will provide deeper characterization of the mechanical for a selected set of heat treatments.
Speaker
Hugo Huttenschmitt
Discover speaker profileMBDA, Bourges, France
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19 - Optimization of heat treatments for a LP – DED Maraging 18Ni300 steel to improve mechanical properties.
Date/Time
21/03/2024
11:05 am -11:25 am
Location
Room 7