Investigation of Powder Injection Moulding, Debinding, and Sintering of CopperAluminum-Manganese Alloy with Polyethylene Glycol, Polymethyl Methacrylate, and Stearic Acid as Binders

Copper Aluminium Manganese (CuAlMn) alloy exhibit the unique ability of shape memory alloy (SMA) which can recover their original shape when exposed to external stimulus typically thermal heat or mechanical stress making them highly desirable for advanced applications. Shape memory alloys based on copper (Cu) exhibit the highest potential for practical applications owing to their robust recovery force, affordability, and suitability for large-scale production. The increasing demand for micro parts in the global market has driven the development of SMA using powder injection moulding (PIM) which is a prominent manufacturing technique used to create intricate parts. This study investigates the PIM process for Cu-Al-Mn alloys using a binder system of polyethylene glycol (Peg), polymethyl methacrylate (Pmma), and stearic acid (Sa). A key focus is on optimizing feedstock properties to ensure uniform powder and binder mixing, minimizing segregation during injection moulding. The ideal powder loading was determined to be 59%, resulting in defect-free moulded parts under optimized parameters: injection temperature of 125°C, pressure of 1.2 MPa, and injection time of 8 seconds. Then the green parts were proceeded with debinding process and sintering conducted under argon atmosphere at 950°C, 1000°C, and 1050°C for three hours. Morphological analyses using SEM revealed that sintering at 950°C and 1000°C did not produce adequate densification, potentially leading to inferior mechanical properties. This study underscores the importance of achieving optimal sintering conditions to enhance microstructure and mechanical performance, providing valuable insights for scalable production of Cu-Al-Mn SMAs through PIM method.