Magnetic toughening method for inhibiting machinery damage of hard and brittle materials

Abstract

The invention provides a magnetic toughening method for inhibiting machinery damage of hard and brittle materials and belongs to the technical field of quality control of machinery process. Accordingto the method, a hard and brittle material is immersed in a clamping mold filled with a magnetorheological fluid, and then the magnetorheological fluid infiltrates into pores, cracks and other defectson the surface layer of the hard and brittle material and liquid-state encapsulation is formed around workpieces; and during machining, a controllable magnetic field is applied such that the magnetorheological fluid is affected by the magnetic force to generate a magnetorheological effect and a high-viscosity elastic film having high yield strength is formed. Thereby, the magnetorheological fluidin the defects on the surface layer of the hard and brittle material is solidified to form a hole-sealed toughening mechanism. The magnetorheological fluid around the material is solidified to form three-dimensional circumferential compressive pre-stress encapsulation, and impact vibration and energy applied by cutters such as a grinding wheel, etc. on the workpieces can be absorbed, and it is helpful for inhibiting the cracks from extending in the deep radial direction or towards side edges. Thereby, defects such as cracks, surface fracture, breaking of edges, etc. are reduced, and machiningquality is improved.

Description

technical field [0001] The invention belongs to the technical field of quality control in mechanical processing, and in particular relates to a method for magnetic toughening to suppress processing damage of hard and brittle materials. Background technique [0002] Engineering ceramics, optical glass and other materials have the characteristics of high hardness and low toughness. Their fracture strength is very sensitive to stress concentration effect and residual tensile stress, and surface breakage and micro-cracks are prone to occur during processing. In addition, it is easy to collapse at the entrance and exit of hard and brittle materials, that is, the phenomenon of edge crushing, mainly due to the impact stress between the tool and the workpiece, and the lack of material support at the edge. Processing damage phenomena such as surface cracks, microcracks, and edge crushing appear randomly, which has become a problem that is difficult to control the quality of hard and ...

AI Technical Summary

Problems solved by technology

[0003] At present, the measures for toughening and suppressing processing damage of hard and brittle materials are roughly summarized as follows: 1) Energy-assisted heating method; laser, electric spark and other energy-assisted heating and cutting methods are used to make the material removal mechanism biased towards ductile domain removal, and inhibit the collapse of ceramics damage, but it is difficult to achieve precise control of the heating process, and it is easy to cause thermal damage to the workpiece

2) Mechanical encapsulation prestress control method: metal materials are used to mechanically enclose hard and brittle material workpieces in the circumferential direction, so as to realize the way of pre-stressing and toughening the surface of the workpiece, which reduces the edge fragmentation of hard and brittle materials. The method has been proven to be effective but is currently less used

3) Material modification and toughening method: through particle toughening, whisker toughening, phase transformation toughening, in-situ toughening and composite toughening, etc., the toughness of hard and brittle materials can be improved, and the fracture strength of materials can be improved. Toughening and strengthening methods need to optimize material components and form multiphase composites, and the process technology is complex

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