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Method for improving fatigue strength after microarc oxidation of aluminium alloy

A technology of micro-arc oxidation and fatigue strength, which is applied in anodic oxidation, liquid chemical plating, metal material coating technology, etc., can solve the problem of decreased fatigue strength of aluminum alloys, internal stress with multiple micro-cracks, and limits the application of micro-arc oxidation technology, etc. question

Inactive Publication Date: 2012-01-18
NANCHANG HANGKONG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, the excellent wear resistance and corrosion resistance of aluminum alloy micro-arc oxidation film has attracted great attention and research interest. The instantaneous temperature in the discharge area can be as high as 10,000°C, causing a large internal stress (tensile stress) and more microcracks in the micro-arc oxidation film, and many micropores on the surface of the sample. Studies have shown that the aluminum alloy micro-arc oxidation film When the thickness reaches more than 25 microns, the fatigue strength of aluminum alloy can be reduced by more than 30%.
Due to the significant influence of aluminum alloy micro-arc oxidation film on the fatigue performance of aluminum alloy, the application of micro-arc oxidation technology in aviation, aerospace and other fields is greatly limited.

Method used

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  • Method for improving fatigue strength after microarc oxidation of aluminium alloy
  • Method for improving fatigue strength after microarc oxidation of aluminium alloy
  • Method for improving fatigue strength after microarc oxidation of aluminium alloy

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Experimental program
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Embodiment approach 1

[0027] After the 2024 aluminum alloy is processed according to the national standard GB4337-84, the micro-arc oxidation experiment and electroless Ni-P plating are carried out, and then the fatigue test is carried out on the WDW-E100D microcomputer-controlled electronic universal testing machine according to the national standard GB 4337-84. The method is cantilever rotation bending loading; R=-1; rotational speed=5000rpm, and the temperature is room temperature.

[0028] The 2024 aluminum alloy is subjected to micro-arc oxidation treatment, and the solution and process parameters of the micro-arc oxidation are as follows: Na 2 SiO 3 8g / L, NaAlO 2 5g / L, NaOH 1g / L, current density 8A / dm 2 , time 3-200 minutes. The thickness of the micro-arc oxidation film was measured by an Elcometer 345 eddy current thickness gauge. From the surface morphology of 12024 aluminum alloy after micro-arc oxidation, it can be seen that the surface is uneven, with a small amount of microcracks an...

Embodiment approach 2

[0032] After the TC4 titanium alloy is processed according to the national standard GB4337-84, the micro-arc oxidation experiment and electroless Ni-P plating are carried out, and then the fatigue test is carried out on the WDW-E100D microcomputer-controlled electronic universal testing machine according to the national standard GB 4337-84. The method is cantilever rotation bending loading; R=-1; rotational speed=5000rpm, and the temperature is room temperature.

[0033] Perform micro-arc oxidation treatment on TC4 titanium alloy, the solution and process parameters of micro-arc oxidation are as follows: Na 2 SiO 3 8g / L, (NaPO 3 ) 6 4g / L, NaOH 1.5g / L, current density 8A / dm 2 , time 2-200 minutes. The thickness of the micro-arc oxidation film was measured by an Elcometer 345 eddy current thickness gauge.

[0034] The formulation and process of electroless Ni-P coating after micro-arc oxidation are as follows: NiSO 4 20-35g / L, CH 3 CH(OH)COOH(lactic acid) 15-30ml / L, NaH ...

Embodiment approach 3

[0037] After the AZ91D magnesium alloy is processed according to the national standard GB4337-84, the micro-arc oxidation experiment and electroless Ni-P plating are carried out, and then the fatigue test is carried out on the WDW-E100D microcomputer-controlled electronic universal testing machine according to the national standard GB 4337-84. The method is cantilever rotation bending loading; R=-1; rotational speed=5000rpm, and the temperature is room temperature.

[0038] Perform micro-arc oxidation treatment on AZ91D magnesium alloy, the solution and process parameters of micro-arc oxidation are as follows: NaAlO 2 5g / L, NaOH 3g / L, current density 8A / dm 2 , time 2-200 minutes. The thickness of the micro-arc oxidation film was measured by an Elcometer 345 eddy current thickness gauge.

[0039] The formulation and process of electroless Ni-P coating after micro-arc oxidation are as follows: NiSO 4 20-35g / L, CH 3 CH(OH)COOH(lactic acid) 15-30ml / L, NaH 2 PO 2 20-40g / L, te...

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Abstract

The invention discloses a method for improving fatigue strength after microarc oxidation of aluminium alloy, which is characterized by comprising the following steps of: 1) performing alkaline cleaning on an aluminium alloy sample; 2) performing microarc oxidation; 3) removing oil; 4) performing ultrasonic cleaning; 5) blow-drying; 6) sensitizing; 7) washing; 8) activating; 9) washing; 10) peptizing; 11) washing; 12) chemically plating Ni-P alloy; 13) washing; and 14) blow-drying.

Description

technical field [0001] The invention relates to a method for improving metal fatigue strength, in particular to a method for improving fatigue strength of aluminum alloy after micro-arc oxidation. Background technique [0002] At present, the main methods to improve the hardness, wear resistance and corrosion resistance of aluminum alloys are ordinary anodic oxidation and hard anodic oxidation technology. The technical characteristics of such methods are low voltage, high current density, and the resulting oxide film is thin And its outer layer is relatively loose, which can improve the wear resistance and corrosion resistance of the aluminum alloy within a certain range. Due to the less heat release in the anodic oxidation process, the internal stress and microcracks produced in the oxide film are less, and the impact on the fatigue performance of aluminum alloys is small. This type of method is widely used in actual production. [0003] In the middle and late 1990s, micro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25D11/04C25D11/24C23C18/36C23C18/18
Inventor 冯长杰杜楠周雅赵晴
Owner NANCHANG HANGKONG UNIVERSITY