Strain Hardening Behaviour of PM Alloys with Heterogeneous Microstructure
Tensile stress-strain and dynamic acoustic resonance tests were performed on Fe-C-Ni- Cu-Mo high-strength steels, characterized by a heterogeneous matrix microstructure and the prevalence of open porosity. All materials display the first yielding phenomenon and, successively, a continuous yielding behavior. This flow behavior can be described by the Ludwigson equation and developes through three stages: the onset of localized plastic deformation at the pore edges; the evolution of plastic deformation at the pore necks (where the austenitic Ni-rich phase is predominant); the spreading of plastic deformation in the interior of the matrix. The analytical modeling of the strain hardening behavior made it possible to obtain the boundaries between the different deformation stages.
Duk Yong Yoon, Suk-Joong L. Kang, Kwang Yong Eun and Yong-Seog Kim
G. Straffelini, "Strain Hardening Behaviour of PM Alloys with Heterogeneous Microstructure", Materials Science Forum, Vols. 534-536, pp. 741-744, 2007