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摘要 鎂合金擁有密度低、比強度和比剛度高、易被人體吸收、彈性模量與人骨相似等特點, 成為現今最具發(fā)展?jié)摿Φ尼t(yī)用金屬材料。但鎂合金的降解速率過快、抗腐蝕性較差，使其應用受限，所以需要進行表面改性。激光微噴丸技術作為新型的表面改性技術在提高效率、改善加工可達性等方面具有其獨特的優(yōu)勢。然而，目前對采用激光微噴丸通過調整醫(yī)用鎂合金表面完整性的辦法來改善其生物腐蝕性能的研究仍缺乏系統(tǒng)性，尤其是激光微噴丸對表面完整性以及表面完整性對生物腐蝕性能的影響。本課題對AZ31B鎂合金經過激光微噴丸后的表面完整性和生物腐蝕性能等作了若干基礎性研究，主要工作如下：

（1）基于鎂合金在生理環(huán)境中腐蝕機理的基本理論，從宏微觀角度分析了激光微噴丸對AZ31B鎂合金材料微觀組織及表面完整性等的影響機理。同時討論了激光微噴丸對材料在生理環(huán)境中腐蝕行為的影響機制。

（2）進行AZ31B鎂合金激光微噴丸實驗，測試試樣在不同參數下的表面完整性，利用形貌識別技術比較多組參數，最終確定最優(yōu)工藝參數，為后續(xù)實驗提供良好試樣保障。

（3）使用CS2350雙單元電化學工作站對激光微噴丸試樣和未噴丸試樣進行電化學腐蝕實驗，通過比較自腐蝕電流和自腐蝕電位的變化，研究不同激光能量、微凹坑間距下激光微噴丸AZ31B鎂合金試樣在Hank’s模擬體液中的腐蝕性能，并對比分析不同激光微噴丸參數下試樣腐蝕性能差異。

關鍵詞：激光微噴丸；AZ31B鎂合金；表面完整性；生物腐蝕性能

 

Abstract Magnesium alloys has become today's most potential medical metallic materials due to its low density, high specific strength and specific stiffness , modulus of elasticity close to the human bone and can be absorbed by the body and so on. But owing to the rapid degradation rate and poor corrosion resistance , magnesium alloys can not be widely used, so it need surface modification. Laser micro-peening technology as a new surface modification technology has its unique advantages to improve the processing of accessibility, improve processing efficiency and so on. However, researchs on improving biological corrosion of medical magnesium alloy by laser micro-peening by adjusting its surface integrity are still lack of systematic, especially the effects on surface integrity and bio-corrision performance by laser micro-peening and surface integrity , respectively .In this paper, several basic research on surface integrity and biological corrosion of AZ31B magnesium alloy treated by laser micro-peening. The main works in this thesis are as follows:

(1) Based on the basic theroy of corrosion mechanism of magnesium alloy in physiological environment，the impact of microstructure and surface integrity of AZ31B magnesium alloy induced by laser micro-peening from the point of view of macro and micro is analyzed. And the impact of corrosion mechanism of materials in physiological environment induced by laser micro-peening is also discussed.

(2) The process tests were carried out of AZ31B magnesium treated with laser micro-peening and the surface integrity of specimens under different parameters were tested. By combining multiple sets of parameters between recognition morphology, the preferred process parameters are finalized and providing a good protection for the subsequent test specimens.

(3) The electrochemical corrosion tests of laser mic-peened and unpeened specimens were processed on the CS2350 two-unit electrochemical workstation, by comparing the changes of corrosion potential and corrosion current, the corrosion performance of AZ31B magnesium alloy in Hank’s by laser micro-peening under different laser energy and spot spacing is analyzed. And the difference between the corrosion mechanism under different laser micro-peening parameters is contrasted and analyzed.

Key words Laser micro-peening    AZ31B magnesium alloy    Surface integrity 

              Biological corrosion performance

 

引     言

鎂合金不僅具有金屬材料所擁有的優(yōu)異機械性能，而且還有高分子材料所具有的良好生物相容性和可降解性，所以作為醫(yī)用植入材料的鎂合金具有非常大的臨床應用前景。但是，鎂合金在人體生理環(huán)境中容易發(fā)生腐蝕，而且在腐蝕過程中所產生的氣體會對植入體周圍組織和細胞產生嚴重影響。目前國內外學者主要通過開發(fā)新型鎂合金和表面處理解決上述問題，但是并沒有取得突破性進展，并且對鎂合金腐蝕性為的研究不夠系統(tǒng)。因此，對鎂合金作為生物醫(yī)用材料在人體生理環(huán)境中的腐蝕過程進行深入研究，可以促進生物醫(yī)用鎂合金材料在臨床上的廣泛應用，為以后更全面深入地研究鎂合金生物應用材料奠定堅實的基礎。

針對上述問題，本文利用激光技術通過調整鎂合金的表面完整性對其表面進行微噴丸處理，以提高生物醫(yī)用鎂合金的耐腐蝕性能。本課題的研究擴展了激光表面處理技術在生物醫(yī)用材料中的應用，為生物醫(yī)用鎂合金激光表面微噴丸的參數選擇提供了新的參考依據。