Powder Injection Molding of Cu–Al–Ni Shape Memory Alloy Components: Feedstock Rheology and Sintering Response
Year: 2026
Type: article
Abstract: Cu–Al–Ni shape memory alloys (SMAs) are promising candidates for engineering applications because of their thermal stability, damping capacity, and relatively low cost compared with Ni–Ti SMAs. Powder injection molding (PIM) is a potential route for producing small and geometrically complex Cu–Al–Ni components; however, its success depends strongly on feedstock rheology, defect-controlled debinding, and suitable sintering response. In this study, 84Cu–12Al–4Ni (wt.%) SMA components were fabricated by PIM using a binder system composed of 65 wt.% paraffin wax, 30 wt.% high-density polyethylene, and 5 wt.% stearic acid. Feedstocks containing 64, 66, and 68 vol.% powder were prepared and rheologically evaluated. The 64 vol.% feedstock showed the most suitable rheological behavior, with favorable flow behavior index, flow activation energy, and general mobility index values. Defect-free green parts were produced by injection molding and subsequently subjected to solvent debinding in n-heptane at 60 ° C for 8 h, followed by thermal debinding at 500 °C for 75 min under Ar. Sintering at 1000 °C for 2.5 h promoted particle bonding and partial consolidation of the Cu–Al–Ni component. FESEM/EDS observations showed elemental interdiffusion together with carbon-rich regions, indicating that further debinding–sintering optimization is required. XRD analysis of the as-sintered component revealed α-Cu/Cu-rich and β/β1 -related phases, suggesting phase development after sintering and furnace cooling.
Source: Jurnal Kejuruteraan
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7225003492