About the MPIF Guide to PM Microstructures
Powder metallurgy microstructures differ from wrought materials in two ways. The major difference is the presence of pores which will vary in size, shape, and distribution depending on density, alloy system, and processing method. Another difference is due to the PM alloy systems themselves. Many PM alloys take advantage of admixed alloy additions, such as copper and nickel in steel alloys, which may or may not result in a completely homogeneous microstructure. The lack of homogeneity has been found to be advantageous in many cases. Due to the inherent flexibility of alloying methods in PM, dual phase, heterogeneous or composite microstructures are quite common and responsible for the unique properties of these materials.
When preparing PM specimens for microstructural analysis, care must be taken to avoid closing the porosity during polishing.
The degree of sinter is a qualitative measurement used to evaluate the effectiveness of the sintering operation. The evaluation is commonly performed as an initial step in the full microstructural analysis of a sample.
This website provides examples of typical microstructures developed during common sintering practices.
Let's see what MPIF Standard 35 Materials for PM Structural Parts has to say about:
Microstructure
PM Material Code Designation
Sincere gratitude is provided to Hoeganaes Corporation, North American Höganäs, Inc., and Rio Tinto Metal Powders for providing the high-quality micrographs, and Powder-Tech Associates, Inc., for verifying the quality of the images..
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