Journal Published Online: 01 July 2020
Volume 9, Issue 4

Microstructural Evolution during Sintering and Fracture Behavior of Iron-Copper-Carbon Compacts Made with Elemental Powders



Iron-copper and iron-copper-carbon have been significant alloy compositions in the ferrous powder metallurgy industry for decades. In most applications in which these alloys are used, the copper is mixed into an iron or low-alloy steel base powder as an elemental particulate additive, with alloying accomplished by diffusion during sintering. In this manuscript, the effect of sintering on the development of the microstructure is investigated, where the copper particles melt and flow into the interconnected pore structure, relocate within the iron-base matrix, and create more interfacial area for diffusion. With this combination of enlarged copper-iron contact area and the presence of the liquid phase, diffusion is improved and enhancements in both physical and mechanical properties are realized. The mechanisms for both alloying and the evolution of the microstructure are described through changes in both compact temperature and the time at sintering temperature. It is demonstrated that alloying strengthens not only the surfaces of the particles, but also many of the most vulnerable sites in the compact, i.e., the locations where neighboring particles are forced into contact during compaction. These sintered particle-to-particle contacts are frequently small in cross-sectional area and often the weakest sites in the final microstructure. Fractography is used to show the change in fracture behavior as copper diffusion is affected by sintering times and temperatures.

Author Information

Murphy, Thomas F.
Hoeganaes Corporation, Cinnaminson, NJ, USA
Lindsley, Bruce A.
Hoeganaes Corporation, Cinnaminson, NJ, USA
Pages: 16
Price: $25.00
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Stock #: MPC20190193
ISSN: 2379-1365
DOI: 10.1520/MPC20190193