What affects the mechanical properties of ferrous PM materials?
: Density: Mechanical properties improve as the amount of porosity is reduced. Tensile strength is almost a linear function of density. Ductility, toughness, and fatigue strength are even more dependent on density; they increase significantly at low levels of porosity. Composition: Different alloying methods (admixing, partially alloying, pre-alloying, and hybrid mixes) are used to achieve the desired chemistry of a material. The composition and alloying method determine the hardenability for a given consolidation and sintering route. Constituents not in solution do not contribute to hardenability. Microstructure: The microstructure depends on the chemistry of the powder, the alloying method used, the sintering time and temperature, the sintering atmosphere, and the cooling rate after sintering.
