Severe plastic deformation method for grain refinement

Abstract

A severe plastic deformation method for grain refinement comprises the following steps: 1) a severe plastic deformation channel is formed by employing three modules, wherein a first module is on the bottom and a second module is arranged above the first module to form a first channel, and a third module arranged on the first module and the second module form a second channel; 2) a workpiece to be processed is disposed in the first channel, and a vertical pressure is applied on the second module to compact the workpiece to be processed; 3) a push force parallel to the first channel is applied on the third module to drive the second module to move a step along a direction against the first channel, so that the workpiece is extruded into the second channel by a step; 4) the positive pressure applied on the second module and the third module push force are released to drive the second module and the third module to retreat to initial positions; 5) step 2-4 are repeated to complete extruding. According to the invention, demands of die material and precision by the severe plastic deformation can be lowered, preparative material scope is widened, integrally uniform refinement crystal grains can be obtained, and a workpiece dimension maintains the same after processing.

Description

technical field [0001] The invention relates to ultra-fine-grain material processing technology, in particular to a large plastic deformation processing method for preparing ultra-fine-grain material. Background technique [0002] The finer the grain of the metal material, the higher its room temperature strength, and the toughness is also improved at the same time. Therefore, grain refinement is the most important and basic method to control the structure of metal materials. The methods of grain refinement mainly include: heat treatment (or deformation heat treatment) using phase transformation and recrystallization, ultra-fast cooling of molten steel, mechanical alloying (or mechanical milling), ultrafine particle sintering, amorphous crystallization, and large Plastic deformation processing and other methods. Among them, the large plastic deformation processing method that has been continuously developed in recent years by causing severe plastic deformation of the mater...

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Problems solved by technology

[0010] The purpose of the present invention is to provide a large plastic deformation grain refinement method, which overcomes the high requirements of the existing large plastic deformation method on the mold, low life, high cost, low production efficiency, and the inability to prepare difficult-to-deform materials. Defects and deficiencies such as limited size can reduce the requirements of large plastic deformation on mold material and precision, expand the range of materials that can be prepared, and obtain uniform and refined grains as a whole, and the size of the workpiece remains unchanged before and after processing

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