A multi-grain scale core-shell structure titanium alloy bulk material and its preparation method

Abstract

The invention discloses a multi-grain-scale core-shell structure titanium alloy block material and a preparation method thereof, and relates to the field of powder metallurgy. The core-shell structure is composed of a coarse wafer layer wrapped with an ultra-fine wafer layer, wherein the coarse wafer The layer is a coarse-grained α-Ti sheet, and the ultra-fine wafer layer is a (α-Ti+β-Ti+δ-TiH) sheet. The preparation method comprises the following steps: putting raw materials into a ball mill tank, mixing them evenly, and then obtaining nanocrystalline mixed powder through high-energy ball milling; molding the nanocrystalline mixed powder into a green body; heating the green body Heating up; moving the heated green body into a preheated extrusion die for hot extrusion to obtain a titanium alloy rod; cooling to room temperature to obtain a multi-grain scale core-shell structure titanium alloy bulk material. The multi-grain scale core-shell structure titanium alloy bulk material provided by the invention has the advantages of high strength and high work hardening ability; and the preparation method greatly reduces the cost of raw materials, the process flow is simple, and has the potential for large-scale production.

Description

technical field [0001] The invention relates to the field of powder metallurgy, in particular to a multi-grain scale core-shell structure titanium alloy bulk material and a preparation method thereof. Background technique [0002] Titanium alloy is an important non-ferrous metal material with excellent physical and chemical properties, such as low density, high specific strength and specific modulus, good plasticity and toughness, strong corrosion resistance, good biocompatibility, and wide temperature range. It plays the role of key structural parts in many important fields such as military industry, automobile industry, aerospace, chemical industry and biomedicine. It is called "21st century metal" and "the third rising metal". [0003] In the automotive industry, safety, energy saving and environmental protection have become the three major themes of industry development. Reducing fuel consumption, reducing emissions of CO, inhalable particulate matter and other toxic gas...

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Problems solved by technology

[0009] (1) Titanium or titanium alloy powder has strong ductility, and it is easy to produce cold welding phenomenon during the ball milling process and stick to the tank wall or grinding ball, resulting in low powder refinement efficiency and low powder extraction rate;

[0010] (2) The cost of titanium alloy spherical powder raw materials is too high, for example, the price of better quality Ti-6Al-4V spherical powder is generally above 2000 yuan / kg;

[0011] (3) The energy introduced by low-energy ball milling is low, and the degree of refinement of powder particles is limited. It is usually difficult to refine the grains on the surface of powder particles to the scale of ultra-fine grains, and the volume fraction of fine-grained regions is small , leading to a limited increase in the strength of bulk materials

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