Search

CN-122007164-A - Method for preparing high-strain low-temperature rolled refined grains of ultra-high-purity aluminum target

CN122007164ACN 122007164 ACN122007164 ACN 122007164ACN-122007164-A

Abstract

The invention discloses a method for preparing ultra-high purity aluminum target by high strain low temperature rolling refined crystal grains, which relates to the technical field of ultra-high purity aluminum target preparation, and comprises the steps of blank preparation and homogenization, blank precooling and deep cooling environment establishment, single-pass deep cooling and strong shearing rolling, deep cooling maintenance and low temperature stabilization treatment after rolling, and subsequent finishing and processing steps, through the synergistic effect of a cryogenic environment, asynchronous rolling, lateral constraint and internal cooling of a roller, a composite strong shear strain field is constructed, and grain extreme refinement and orientation randomization are synchronously realized in single-pass rolling. The invention abandons the traditional multi-pass accumulated deformation mode, solves the problem that fine crystals and isotropy are difficult to achieve synchronously in the prior art, obtains the equiaxial ultrafine crystal non-textured structure, can meet the use requirements of high-end manufacturing fields such as semiconductors, flat panel displays and the like on target materials, and provides a reliable technical approach for the efficient preparation of ultra-high-purity aluminum target materials.

Inventors

  • XIE ZHENGYE
  • YANG HUIJUAN
  • YANG RUIYU

Assignees

  • 运城隆希铝业有限公司

Dates

Publication Date
20260512
Application Date
20260204

Claims (8)

  1. 1. The method for preparing the high-strain low-temperature rolling refined grains of the ultra-high-purity aluminum target is characterized by comprising the following steps of: Firstly, preparing and homogenizing a blank, namely machining an ultrahigh-purity aluminum cast ingot to obtain a blank, and then homogenizing at a high temperature; Step two, establishing a cryogenic environment and pre-cooling the blank, namely pre-cooling the blank in a liquid nitrogen environment to reduce the overall temperature of the blank to below 150 ℃ below zero; Step three, single-pass deep-cooling strong shearing rolling, namely feeding the precooled plate blank into a rolling mill for single-pass rolling under the continuous cooling of liquid nitrogen atmosphere or liquid nitrogen spraying, wherein a linear speed difference exists between an upper working roll and a lower working roll of the rolling mill, the speed ratio range is 1.2-2.0, a lateral restraint device is arranged at a roll gap inlet of the rolling mill, the lateral restraint device is tightly attached to two sides of the plate blank in the width direction to limit the flow of the plate blank in the width direction in the rolling process, and the rolling reduction of the single-pass rolling is 70-85%; Step four, deep cooling maintenance and low temperature stabilization treatment, namely immediately immersing a rolled plate in liquid nitrogen for 10 to 30 minutes after single-pass rolling is finished, and slowly raising the temperature to room temperature in a low-temperature environment of 50 ℃ below zero to 0 ℃; And fifthly, carrying out subsequent finishing and processing, namely leveling, cutting and surface processing on the processed plate to obtain an ultra-high purity aluminum sputtering target finished product.
  2. 2. The method for producing ultra-high purity aluminum target material by high strain low temperature rolling refined grain according to claim 1, wherein in the first step, the purity of the ultra-high purity aluminum is not lower than 99.999%; The temperature of the high-temperature homogenization treatment is 450-600 ℃, the heat preservation time is 10-48 h, and the treatment atmosphere is vacuum or high-purity inert gas protective atmosphere.
  3. 3. The method for refining grains by high-strain low-temperature rolling for preparing the ultra-high-purity aluminum target according to claim 1, wherein in the second step, the pre-cooling time is 30min to 2h, so as to ensure that the temperature of the slab core is stabilized below 150 ℃.
  4. 4. The method for producing ultra-high purity aluminum target by high strain low temperature rolling refined grain according to claim 1, wherein in the third step, the lateral restraint device is a high strength alloy baffle plate fixedly installed on a rolling mill frame, the single side gap between the high strength alloy baffle plate and the slab width direction is less than 0.5mm, and the height of the baffle plate is not less than the thickness of the slab before rolling.
  5. 5. The method for refining grains by high-strain low-temperature rolling for preparing ultra-high-purity aluminum targets according to claim 1, wherein in the third step, an inner cooling channel is arranged on each of the upper working roll and the lower working roll of the rolling mill, and liquid nitrogen or an ultra-low-temperature cooling medium is continuously introduced into the inner cooling channel in the rolling process so as to maintain the surface temperature of the working rolls at an ultra-low temperature state.
  6. 6. The method for producing ultra-high purity aluminum target by high strain low temperature rolling refined grain according to claim 1, wherein in the third step, the single pass rolling forms a dynamically varying composite shear strain field inside the slab, the composite shear strain field being composed of a dominant shear strain produced by asynchronous rolling coupled with an additional multidirectional shear strain produced by lateral constraint.
  7. 7. The method for producing ultra-high purity aluminum target by high strain low temperature rolling refined grain according to claim 1, wherein in the fourth step, the temperature rising rate of slowly rising to room temperature is not more than 5 ℃.
  8. 8. The method for refining grains by high-strain low-temperature rolling for preparing the ultra-high-purity aluminum target according to claim 1, wherein through the single-pass sub-cryogenic high-shear rolling and subsequent treatment, an equiaxed ultra-fine grain structure with the average grain size between 50nm and 200nm is formed inside the ultra-high-purity aluminum sputtering target finished product, and the grain orientations are distributed in a highly random manner.

Description

Method for preparing high-strain low-temperature rolled refined grains of ultra-high-purity aluminum target Technical Field The invention relates to the technical field of preparation of ultra-high-purity aluminum targets, in particular to a method for preparing high-strain low-temperature rolled refined grains of an ultra-high-purity aluminum target. Background The ultra-high purity aluminum sputtering target material is an indispensable key raw material in the high-end manufacturing fields of semiconductors, flat panel displays and the like. The microstructure of the target, particularly the grain size and orientation distribution, directly determines the quality, uniformity and final device performance of the sputtered film. The ideal target structure should have the characteristics of fine grains and random orientation so as to ensure stable sputtering rate and uniform film thickness. Therefore, how to efficiently and reliably prepare the ultra-high-purity aluminum target material with both nano-scale fine crystals and highly isotropic structures is always an important direction for solving the technical problems in the field. In order to refine grains, the prior art generally adopts a deformation processing path with multiple passes and multiple working procedures. For example, the invention patent publication No. CN110205590A discloses a rolling method of an ultra-high purity aluminum sputtering target. The method realizes large deformation by a double-pass strategy of rolling with half reduction, rewinding after biting and rolling with full reduction, but the method basically still belongs to the category of multi-pass rolling, does not involve an ultralow temperature environment, has limited grain refinement capability and has a final grain size of about 150 microns. Another prior art publication No. CN107119244B is a method for preparing a high preferred orientation fine-grain ultra-high purity aluminum target, which comprises hot rolling at 50 ℃ to 300 ℃ and subsequent cold rolling, the reduction in pass is controlled to 40% to 50%, and the temperature rise is controlled by inter-pass cooling. Although fine crystals can be obtained by the method, strong rolling textures are easy to introduce in multi-pass rolling, so that the target performance shows anisotropy. In addition, the technical proposal adopts a composite process of multidirectional forging and room temperature multipass rolling, the working procedure is more complicated, and the problems of fine crystals and isotropy can not be synchronously solved in single deformation. In summary, the prior art schemes all rely on the accumulation deformation mode of multiple passes and multiple processes, and the limitation is that the nanoscale grain refinement and the highly random equiaxed non-textured structure formation of the ultra-high purity aluminum cannot be synchronously realized in single rolling deformation. Multiple processes lead to complex flow and low efficiency, and single pass rolling with high rolling reduction is simply pursued, and strong texture is difficult to avoid. Therefore, it is needed to develop a new rolling deformation principle and process, which can cooperatively solve the contradictory requirements of fine grain and isotropy in a compact process. The present invention has been made to overcome the above-mentioned drawbacks of the prior art. Disclosure of Invention The invention aims to make up the defects of the prior art, provides a method for preparing high-strain low-temperature rolling refined grains of an ultra-high-purity aluminum target, constructs a dynamically-changed composite high-shear strain field through the synergistic effect of a cryogenic environment, asynchronous rolling, lateral constraint and internal cooling of a roller, synchronously realizes the extreme refinement and orientation randomization of the ultra-high-purity aluminum grains in single-pass rolling, abandons a traditional multi-pass processing mode, efficiently obtains a nanoscale equiaxed non-textured structure, and meets the severe requirements of a high-end sputtering target on a microstructure. The invention provides a method for preparing high-strain low-temperature rolled refined grains of an ultra-high-purity aluminum target, which aims to solve the technical problems and comprises the following steps: Firstly, preparing and homogenizing a blank, namely machining an ultrahigh-purity aluminum cast ingot to obtain a blank, and then homogenizing at a high temperature; Step two, establishing a cryogenic environment and pre-cooling the blank, namely pre-cooling the blank in a liquid nitrogen environment to reduce the overall temperature of the blank to below 150 ℃ below zero; Step three, single-pass deep-cooling strong shearing rolling, namely feeding the precooled plate blank into a rolling mill for single-pass rolling under the continuous cooling of liquid nitrogen atmosphere or liquid nitrogen spraying, wherein a linear speed dif