An Equal Channel Angle Drawing Method for Efficient and Continuous Preparation of Ultra-fine-grained Pure Titanium at Room Temperature

Abstract

The invention provides an equal-channel corner drawing method for efficiently and continuously preparing ultra-fine-grained pure titanium at room temperature. The method is realized through an equal-channel corner drawing mold composed of four modules A, B, C, and D. The steps include: using pure Titanium rods or plates are used as starting materials. After annealing, equal channel corner drawing molds are made according to the cross-sectional shape and size of the starting raw materials; the blank is polished, and its surface and the surface of the four molds pre-formed equal channel corner channels are coated Cover with lubricant; place the blank in an equal-channel corner channel formed by four molds with an angle of 90° or 110°, and then place it on the drawing machine. Control the drawing speed at 2 to 100mm / s to make the blank pass through at a uniform speed. In the equal channel corner channel, after each pass of drawing is completed, remove the head and tail of the drawn piece, rotate the drawn piece clockwise or counterclockwise by an angle θ, and then reposition it in the equal channel corner channel to continue drawing. After 2 to 12 passes of drawing, ultra-fine grained pure titanium material is obtained.

Description

technical field [0001] The invention belongs to the technical field of ultrafine-grain material processing, and in particular relates to an equal-channel corner drawing method for efficiently and continuously preparing ultrafine-grain pure titanium at room temperature. Background technique [0002] Pure titanium (Ti) and its alloys have good corrosion resistance, high specific strength, good biocompatibility, non-toxic, non-magnetic, low elastic modulus, fatigue resistance, poor electrical and thermal conductivity, etc., and are widely used in surgical implant materials. For example, artificial joints, bone plate screws and dental implants are widely used in fields such as artificial joints, and become the main development direction of medical metal materials in the future. Ti-6A1-4V alloy is widely used clinically at present. Studies have shown that the Al and V metal ions released by long-term corrosion in the human body are harmful to the human nervous system and respirat...

AI Technical Summary

Problems solved by technology

[0003] Metallic pure Ti has a close-packed hexagonal structure, less slip system at room temperature, poor plasticity, and problems such as difficulty in severe plastic deformation at low temperature and deformation cracking.

The large-scale plastic deformation methods of pure Ti that have been studied more include equal-diameter angular extrusion (such as patents CN101580924A, CN101624690A, CN103343303A, CN103981472A, CN104690496A, CN103252377A, CN105821360A), high-pressure torsion (such as patents CN102234732A, CN10202A), and multi-directional forging. (such as patent CN103320734A), etc., most of them have some problems, the most important of which are the limited size of the prepared materials and low production efficiency. In addition, there are also high mold requirements, high cost, uneven organization, and low material utilization. Disadvantages, especially for hard-to-deform materials with a close-packed hexagonal structure, the forming temperature is high (>200°C) and the deformation speed is slow (0.025-2.5mm / s), which has always been the difficulty that the large plastic deformation method needs to break through

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