Changes in the Properties in Bimodal Mg Alloy Bars Obtained for Various Deformation Patterns in the RSR Rolling Process

Abstract

The paper presents the theoretical and experimental research conducted to date regarding the possibility of obtaining round bars from AZ31 magnesium alloy with a bimodal structure rolled in the radial shear rolling process (RSR) technology. There is no analysis of the impact of the deformation path (distribution of deformation in individual passes) on the mechanical properties and the obtained bar structure. The feedstock, namely, AZ31 magnesium alloy round bars with a diameter of 30 mm, were rolled in RSR to the final diameter of 15 mm with different levels of deformation in successive passes, at a temperature of 400 °C. The bars obtained as a result of the RSR rolling process have different hardness on the cross-section as well as a characteristic gradient grain size distribution. Based on the conducted research, it can be concluded that the use of a larger number of passes with a smaller cross-section reduction will result in an improved formation of a bimodal structure consisting of a highly fragmented near-surface structure and in the half of the radius of the structure of fragmented grains at the boundaries of larger grains.

Analysis of Temperature Influence on Strain–Speed Parameters of Radial-Shear Rolling of Al-Zn-Mg-Ni-Fe Alloy

“…The length of the surface trajectory L β in the deformation zone can be approximately calculated based on the volume constancy law taking into account the elongation ratio μ , the angle of trajectory β 1 , and the number of deformation cycles N [ 24 , 25 ]: …”

“…With the development of computer programs for simulation, the use of the finite element method (FEM) is an available solution to this problem. Software systems for the simulation of metal-forming processes allow engineering analysis of the main process parameters to be performed without significant time and financial costs [ 19 , 20 , 21 , 22 , 23 , 24 ].…”

Obtaining an Equiaxed Ultrafine-Grained State of the Longlength Bulk Zirconium Alloy Bars by Extralarge Shear Deformations with a Vortex Metal Flow

“…The radial shear rolling method has become in recent years increasingly popular for significant structure refinement of steel [ 16 , 19 , 20 , 21 , 22 , 23 , 24 ], titanium [ 25 , 26 ], aluminum and magnesium alloys [ 27 , 28 , 29 ], copper [ 16 ], zirconium [ 30 ], and other alloys [ 31 , 32 , 33 , 34 , 35 ]. However, in many cases, the deformation on the one setup is used, and the total deformation by diameter does not exceed ε = 50%.…”

Simulation of the Kinematic Condition of Radial Shear Rolling and Estimation of Its Influence on a Titanium Billet Microstructure

“…Computer simulation, including FEM-based, is applied for the estimation of the stress-strain state parameters and temperature distribution through the rolled billet's volume during RSR [28][29][30][31][32]. Some research has been dedicated to the joint use of computer simulation and experimental RSR for different purposes: the prediction of a possible billet's fracture during RSR [11], the estimation of the features of the stressstrain state parameters' distribution during the stationary and nonstationary stages of RSR [33][34][35], research of the billet's microstructure and property formation [36][37][38][39], and the estimation of the stress-strain state parameters' distribution in the deformation zone during RSR [14,20,40,41]. It has been noted [11,35] that further investigations of three-high screw rolling are necessary because the billet's stress-strain state features and their influence on the billet's microstructure have not been completely detected.…”