Method for preparing gradient nanostructured metal material by ultra-precision machining technology

Abstract

The invention provides a method for preparing a gradient nanostructured metal material by an ultra-precision machining technology. The method comprises the following steps of providing a cylindrical metal material workpiece to be processed, pretreating the cylindrical metal material workpiece, rotating the pretreated cylindrical metal material workpiece in a straight line connected with the circlecenters of the upper and lower bottom surfaces of the cylinder as an axis; in the liquid nitrogen environment, a diamond tool is adopted to carry out turning machining on the surface of the rotatingcylindrical metal material workpiece, in the turning machining process, the nose line of the diamond tool is parallel to the outer surface of the cylindrical metal material workpiece, and the diamondtool moves back and forth along the axial direction on the surface of the rotating cylindrical metal material workpiece to obtain the gradient nanostructured metal material; the depth of the gradientnanostructure tissue of the gradient nanostructure metal material is 200-8000 micrometers, and the gradient nanostructure tissue is composed of a nano twin crystal, a nanocrystalline, an ultra-fine twin crystal, an ultra-fine crystal, a deformed coarse crystal and an initial coarse crystal from the surface to the core part in sequence. 本发明提供了一种超精密加工技术制备梯度纳米结构金属材料的方法，包括如下步骤：提供待处理的圆柱形金属材料工件，将所述圆柱形金属材料工件进行预处理后，使预处理后的圆柱形金属材料工件以所述圆柱形的上下两个底面的圆心连接的直线为轴进行旋转；在液氮环境下，采用金刚石刀具对旋转的所述圆柱形金属材料工件的表面进行车削加工处理，且所述车削加工处理的过程中，所述金刚石刀具的刀尖线平行于所述圆柱形金属材料工件的外表面、并对旋转的所述圆柱形金属材料工件的表面沿轴向做往返运动，得到所述梯度纳米结构金属材料；其中，所述梯度纳米结构金属材料的梯度纳米结构组织的深度为200～8000μm，且所述梯度纳米结构组织由表面至芯部依次为纳米孪晶、纳米晶、超细孪晶、超细晶、变形粗晶和初始粗晶。