Influence of deformation on metal structure in the forward microextrusion process.

Investigation results presented in the work relate to the impact of tool roughness on the material plastic flow during forward microextruding of metal. Investigation process consists of the experimental and numerical parts. In the experimental one, forward microextrusion of annealed material using the toolkit author's copyright project was performed. The tests were conducted to compare deformation of the material extruded in containers with different roughness. As a result, obtained images of deformed material structures are presented and compared. Numerical part relates to simulations of analogous microextrusion processes conducted using DEFORM software. Tool roughness was modeled in the form of rigid triangular waves, whose geometric parameters were based on the roughness profiles obtained for the experimental tools. Depth and length of the triangular elements were determined using the motives method. Distribution fields of the effective stress, strain and the flow velocities are presented and compared. Based on obtained data, concept of determining of the parameter which can help to define the appearance of structural size effect resulting from the influence of container roughness is also presented. [ABSTRACT FROM AUTHOR]