Method for optimizing grain size and uniformity of tantalum plate

Abstract

The invention discloses a method for optimizing grain size and uniformity of a tantalum plate. The method comprises the following steps: 1, a tantalum cast ingot with a circular section shape is flattened by using a rapid forging machine in a room-temperature environment to obtain a tantalum blank with a rectangular section shape; 2, saw cutting is conducted, and a tantalum blank with the square cross section is obtained; 3, forging and rounding are conducted after heat preservation, and a bar blank with a circular cross section is obtained; 4, primary annealing treatment is performed to obtain an annealed bar billet; 5, the bar billet is extruded after heat preservation to obtain a plate blank with a rectangular section; 6, secondary annealing treatment is conducted, and an annealed plateblank is obtained; 7, rolling is performed to obtain a plate; and 8, third-time annealing treatment is conducted, and a finished tantalum plate is obtained. By the method, preparation of the medium-thickness tantalum plate with the thickness ranging from 5 mm to 20 mm can be achieved, the grain size is superior to 6.5 levels, the maximum grain size is less than or equal to 38 [mu]m, the grain size of the plate in the thickness direction is uniform, and the grain size level difference between a surface layer and the core portion is within 0.5 level.

Description

technical field [0001] The invention belongs to the technical field of material processing, and in particular relates to a method for optimizing the grain size and uniformity of tantalum plates. Background technique [0002] Metal tantalum has high melting point, low vapor pressure, low evaporation rate at high temperature, low ductile-brittle transition temperature (DBTT) and special dielectric properties, and can be widely used in the preparation of sputtering targets for integrated circuits; in addition, tantalum also has high density , a certain tensile strength and good ductility, and has higher penetration than copper, and is also one of the ideal materials for medicine-shaped masks. Since the size and uniformity of the grain directly affect the performance of the sputtered film and the performance of the drug mask, the smaller the grain size, the higher the deposition rate and the better the uniformity of the sputtered film, and the better the uniformity of the drug m...

AI Technical Summary

Problems solved by technology

However, in the prior art, the fineness and uniformity of the grain size in the thickness direction cannot be guaranteed when preparing plates with a thickness greater than 5mm, so that the finished plate not only has a grain size of more than 50 μm, but also has a grain size difference greater than 2 in the thickness direction. , can not meet the rapid development of integrated circuits and the needs of heavy blows

[0004] There are three reasons for the above phenomenon of medium and thick plates: one is that the raw material tantalum ingot grains are coarse and uneven, especially the original grains of the tantalum ingot melted by electron beam are abnormally coarse, and the edge of the ingot is slightly smaller The equiaxed crystals of tantalum have a size of about 10-50 mm, and the center is an abnormally thick columnar crystal, with a maximum size of 100 mm. Second, due to the poor forgeability of tantalum, even after repeated upsetting forging, the plastic deformation is distributed from the surface to the core. It is always uneven; the third is that the total processing rate of medium-thick plate rolling is small, and it is difficult to obtain plates with fine and uniform grains

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