Page 51 - MSAM-3-2

Materials Science in Additive Manufacturing Heat treatment on bimetallic parts

A B

C

D

Figure 1. The illustration of the ES-AM process and the fabricated 17-4PH/IN625 bimetal part. (A) An illustration ES-AM process with a dual nozzle
system (B) A bimetallic material after printing. (C) The top perspective of the sintered component. (D) Profile of the sintered component, showcasing
geometrical details. Scale bars: 2 mm.
Abbreviation: ES-AM: Extrusion-based sintering-assisted additive manufacturing.

Table 1. Material properties for 17‑4PH and IN625 filament uniformity. One of the recommended heat treatment
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and optimized printing parameters for 17‑4PH/IN625 procedures for the IN625 alloy involves subjecting it
bimetallic green part to a solutionizing operation at 1150°C. This thermal
Parameters 17‑4PH IN625 processing step serves to eliminate compositional
inhomogeneities, eliminate secondary phases present,
Filament trigger recrystallization phenomena, and promote grain
Version V2 - coarsening. The aging temperature and duration were
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Diameter 1.75 mm 1.75 mm adjusted for specific applications to balance strength
Specification 400 cc/spool 200 cc/spool and toughness while controlling tempered martensite
Composition 20 vol.% wax, 20 vol.% and precipitation. In addition, an aging heat treatment
polyethylene, and 60 vol.% powder was employed (482°C for 1 h holding time), following
Optimized printing parameters HT8 to enhance hardness. Rapid cooling through water
Nozzle temperature 230°C 210°C quenching was implemented for the samples to promote
Bed temperature 80°C 80°C expedited heat extraction and mitigate the potential for
Chamber temperature 60°C 60°C carbide precipitation, especially within the temperature
regime of 1150°C sustained for 8 h. Figure 2 illustrates the
Nozzle size 0.4 mm 0.4 mm
Layer thickness 0.1 mm 0.1 mm heat treatment conditions used during the experiments.
Infill density 100% 100% 2.2. Microstructure characterizations and
Speed 40 mm/s 40 mm/s mechanical properties
Infill orientation 45° 135° To investigate the microstructure and microhardness,
bimetallic samples were prepared in both as-sintered
of martensite. Considering factors such as the presence and heat-treated states. Pore distribution and grain
of NbC and oxides, as well as the dimensions of prior morphology were analyzed using optical microscopy
austenite grain and martensite lath, the homogenization (OM; Olympus DSX 510, Olympus, Japan) and scanning
temperature was set at 1150°C to ensure adequate electron microscopy (SEM; Supra 55-VP, Zeiss, Germany).

Volume 3 Issue 2 (2024) 4 doi: 10.36922/msam.3281