【摘要】：由于鎂合金在室溫及高溫下表現(xiàn)出低的硬度，低的強度，耐蝕性差等性能阻礙了其在工業(yè)中的應(yīng)用，采用添加增強體來制備增強鎂基復(fù)合材料可以很好的改善鎂合金基體的綜合力學性能。本文采用SiC顆粒作為增強體制備了SiCp/AZ91D鎂基復(fù)合材料，系統(tǒng)的研究SiC顆粒增強鎂基復(fù)合材料的增強機理，微觀組織結(jié)構(gòu)，，斷口形貌，綜合力學性能。 本文采用不同制備工藝制備復(fù)合材料，分別采用擠壓鑄造法和重力鑄造法制備SiCp/AZ91D鎂基復(fù)合材料，采用正交實驗的方法研究了顆粒含量，顆粒尺寸，澆注溫度，擠壓壓力對復(fù)合材料性能的影響，并通過極差分析方法分析得出了影響因素的顯著性順序及最優(yōu)化的實驗參數(shù)。重力鑄造主要研究顆粒含量，顆粒尺寸，澆注溫度對材料性能的影響，結(jié)合金相組織，斷口形貌，力學性能，從微觀角度研究了顆粒增強的機理，材料的斷裂機制，顯微組織。并對擠壓鑄造法和重力鑄造法制備復(fù)合材料的密度，抗拉強度，伸長率，硬度等力學性能及微觀組織進行對比分析，實驗結(jié)果表明采用擠壓鑄造法制備的SiC顆粒增強AZ91D復(fù)合材料的綜合力學性能較重力鑄造法制備的復(fù)合材料的綜合力學性能更加優(yōu)良。 著重研究擠壓鑄造法制備SiCp/AZ91D鎂基復(fù)合材料中顆粒含量及擠壓壓力對材料顯微結(jié)構(gòu)及力學性能的影響，實驗結(jié)果表明，當擠壓壓力一定時，隨著顆粒含量的增加材料的硬度呈上升趨勢，而伸長率呈下降趨勢，抗拉強度先增大后減小。當顆粒含量一定時，隨著擠壓壓力的增大材料的抗拉強度及伸長率先增大后減小，當擠壓壓力為100MPa時達到最高。 在最優(yōu)的實驗參數(shù)下，采用擠壓鑄造制備SiCp/AZ91D鎂基復(fù)合材料，并對復(fù)合材料進行固溶與時效處理，研究結(jié)果表明，固溶時效后材料的力學性能有了很大的提到。熱處理之前抗拉強度為193.1MPa，熱處理之后抗拉強度為231.5MPa，提高了19.9%，熱處理之前伸長率值為4.32%，熱處理之后為5.38%，提高了24.5%，熱處理之前硬度值為73.23HB，熱處理之后硬度值為81.13HB，提高了10.8%。
文內(nèi)圖片：
圖片說明：HFC-134a氣瓶
[Abstract]:Due to the low hardness, low strength and poor corrosion resistance of magnesium alloy at room temperature and high temperature, the application of magnesium alloy in industry is hindered. The comprehensive mechanical properties of magnesium alloy matrix can be improved by adding reinforcements to prepare reinforced magnesium matrix composites. In this paper, SiCp/AZ91D magnesium matrix composites were prepared by using SiC particles as reinforcement system. The strengthening mechanism, microstructure, fracture morphology and comprehensive mechanical properties of SiC particles reinforced magnesium matrix composites were systematically studied. In this paper, SiCp/AZ91D magnesium matrix composites were prepared by different preparation processes, and SiCp/AZ91D magnesium matrix composites were prepared by squeeze casting and gravity casting, respectively. the effects of particle content, particle size, pouring temperature and extrusion pressure on the properties of the composites were studied by orthogonal experiment, and the significant order of influencing factors and the optimized experimental parameters were obtained by means of extreme difference analysis. Gravity casting mainly studied the effects of particle content, particle size and pouring temperature on the properties of the material. Combined with metallographic structure, fracture morphology and mechanical properties, the mechanism of particle reinforcement, fracture mechanism and microstructure of the material were studied from a microscopic point of view. The mechanical properties and microstructure of the composites prepared by squeeze casting and gravity casting were compared and analyzed. The experimental results show that the comprehensive mechanical properties of SiC particle reinforced AZ91D composites prepared by squeeze casting are better than those prepared by gravity casting. The effects of particle content and extrusion pressure on the microstructure and mechanical properties of SiCp/AZ91D magnesium matrix composites prepared by squeeze casting were studied emphatically. the experimental results show that when the extrusion pressure is constant, the hardness of the material increases with the increase of particle content, while the elongation decreases, and the tensile strength increases at first and then decreases. When the particle content is constant, the tensile strength and extension of the material increase at first and then decrease with the increase of extrusion pressure, and reach the highest when the extrusion pressure is 100MPa. Under the optimal experimental parameters, SiCp/AZ91D magnesium matrix composites were prepared by squeeze casting, and the solid solution and aging treatment of the composites were carried out. the results show that the mechanical properties of the composites after solid solution aging are greatly mentioned. The tensile strength before heat treatment is 193.1 MPA, the tensile strength after heat treatment is 231.5 MPA, the tensile strength is increased by 19.9%, the elongation value before heat treatment is 4.32%, after heat treatment is 5.38%, the increase is 24.5%, the hardness value before heat treatment is 73.23HB, and the hardness value after heat treatment is 81.13HB, which is 10.8%.
【學位授予單位】：中北大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB333

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