Variations in defect substructure and fracture surface of commercially pure aluminum under creep in weak magnetic field

Abstract

Commercially pure polycrystalline aluminum of grade A85, as a test material, is investigated. Using scanning and transmission electron microscopy the aluminum fine structure and fracture surface are analyzed. Fractures are studied in the regime of creep with and without a simultaneous effect of 0.3-T magnetic field. It is found that the application of a magnetic field in a linear stage of creep leads to substructure imperfection increasing. Furthermore, the magnetic field effect on aluminum in the process of creep causes the average scalar density of dislocations to increase and induces the process of dislocation loop formation to strengthen. Fractographic investigation of the fracture surface shows that in the fibrous fracture zone the average size of plastic fracture pits decreases more than twice under creep in the condition of external magnetic field compared with in the conventional experimental condition. In a shear zone, the magnetic field causes the average size of fracture pits to decrease. Experimental data obtained in the research allow us to conclude that the magnetic field effect on aluminum in the process of creep leads to the fracture toughness value of the material decreasing, which will affect the state of defect substructure of the volume and surface layer of the material. The influence of the magnetic field is analyzed on the basis of the magneto-plasticity effect.

Thermomechanical response of aluminum alloys under the combined action of tensile loading and laser irradiations

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Study on electropulsing assisted turning process for AISI 304 stainless steel

“…17 Gromov et al studied the evolution of defect substructure, fracture surface and dislocation substructure of aluminum creep under the action of the weak electric potential. 18,19 Conrad et al proposed that the high mobility of dislocations due to the electric current played an important role in such effects via the studies on the influence of electropulsing to the recrystallisation of metallic material. 13,[20][21][22][23] A number of researches on the applications of electropulsing, electric field and electromagnetic field in rolling and drawing process for metal materials have been reported, while the studies on using them in turning process can rarely be found to date.…”

“…17 Gromov et al studied the evolution of defect substructure, fracture surface and dislocation substructure of aluminum creep under the action of the weak electric potential. 18,19 Conrad et al proposed that the high mobility of dislocations due to the electric current played an important role in such effects via the studies on the influence of electropulsing to the recrystallisation of metallic material. 13,20–23…”