Injection molding of nickel based 625 superalloy: Sintering, heat treatment, microstructure and mechanical properties

• Published in: Journal of alloys and compounds Vol. 546; pp. 192 - 207
• Main Authors: Özgün, Özgür, Özkan Gülsoy, H., Yilmaz, Ramazan, Findik, Fehim
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 05.01.2013; Elsevier
• Subjects: 625 Superalloy; Alloys; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Mechanical and acoustical properties; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Mechanical tests; Microstructure; Nickel base alloys; Physical properties of thin films, nonelectronic; Physics; Powder injection molding; Scanning electron microscopy; Sintering; Sintering (powder metallurgy); Solid solution, precipitation, and dispersion hardening; aging; Superalloys; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Treatment of materials and its effects on microstructure and properties; Tribology and hardness; Powder injection molding; 625 Superalloy; Microstructure; Sintering; Nickel base alloys; Temperature dependence; Scanning electron microscopy; Nickel alloys; Thermal ageing; Tensile tests; Mechanical properties; XRD; Mechanical tests; Hardness; Superalloys; Heat treatments; Cast alloy; Solution heat treatment; Transmission electron microscopy; Thermal parameter; Injection molding; Property structure relationship
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.08.069

► Sintering, microstructural and mechanical properties of injection molded nickel based 625 superalloy were studied. ► The maximum sintered density achieved this study was 98.3% at 1300°C for 3h. ► Tensile strength of 674MPa, elongation of 40.6% and hardness of 303 HV were achieved for sintered and heat treated conditions. This study concerns determination of optimum sintering and thermal process parameters for Ni-based alloy 625 superalloy formed by the method of powder injection molding (PIM). Samples, formed from the feedstock by mixing the prealloyed 625 powder with a multi-component binding system, are made subject to sintering at different temperatures following the debinding process. Samples that are sintered under such conditions giving way to the highest relative density (3h at 1300°C), are aged after they have been subject to solution treated thermal process. Sintered, solution treated and aged samples have been subjected to microstructural analysis and mechanical test. Mechanical tests such as hardness measurement and tensile test as well as microstructural characterization such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis all have shown that the aging thermal process increases strength of the material. However, it is observed that alloy 625 produced by the method of PIM is at such level to compete with the characteristics of cast alloy 625.