Evaluation of the porous material plasticity when direct extruded

Abstract

This article deals with results received after the investigation of caked porous metal plasticity from stabilized copper powder by the direct extrusion. To describe the plasticity dependence on the scheme of tense condition the surface of contiguous deformations was used, which describes the dependence of the accumulated to the destruction moment degree of the material base deformation on two indices of tense condition. In the process of investigation the surface of contiguous deformations for caked porous material on the basis of stabilized copper powder was received. The article suggests the assessment criteria of probability of porous solids destruction by high plastic deformations in which the history of loading is defined by spatial trajectories in coordinates: the accumulated deformation of the material base, inflexibility exponent of its tense condition, the parameter of Nadai-Lode, and the plasticity dependence on the scheme of tense condition is described by the surface of contiguous deformations. To denote the loading trajectories of free points of plastic field in the chosen space of the tense condition indices, it’s necessary to have the information about the tense condition and about the low of its changing in any point of deforming billet. To denote the stress field, the method experimental-calculation was used, in which the components of speed deformations tensor was defined by visioplasticity method. The offered method of porous solids plasticity evaluation gave the possibility to increase the calculation precision of the used plasticity resource and establish the influence of the main parameters of the process of direct extrusion on the regularity of damage accumulation of the porous metal compression.

Keywords

• plasticity
• porosity
• stress
• deformation
• failure
• direct extrusion