【摘要】：使用表面化學(xué)鍍鎳的短碳纖維為增強(qiáng)體、AZ91D粉為基體金屬,用粉末冶金法和熱擠壓工藝制備鎂基復(fù)合材料,用SEM、TEM-EDS、拉伸和動態(tài)熱機(jī)械分析(DMA)等手段表征其微觀形貌、界面結(jié)構(gòu)、力學(xué)性能和阻尼性能,研究了金屬鎳涂層短碳纖維對AZ91D鎂基復(fù)合材料的界面和阻尼性能的影響。結(jié)果表明,碳纖維在復(fù)合材料中分布均勻,沿著擠壓方向定向排列;鎳涂層改善了碳纖維與AZ91D基體之間的潤濕性;不同頻率的應(yīng)變譜和G-L特征線都表明:復(fù)合材料的阻尼機(jī)制,除了位錯之外還有其他機(jī)制;隨著應(yīng)變頻率的提高復(fù)合材料的阻尼機(jī)制由以界面滑移為主轉(zhuǎn)變?yōu)橐晕诲e為主。隨著溫度的升高涂層碳纖維增強(qiáng)鎂基復(fù)合材料的阻尼容量增大,在250~300℃出現(xiàn)一個阻尼峰。隨著頻率的提高阻尼峰值的溫度移向高溫,表現(xiàn)出熱激活弛豫過程的特征,根據(jù)Arrhenius公式計算出其熱激活能(H)為3.448 e V。
[Abstract]:Magnesium matrix composites were prepared by powder metallurgy and hot extrusion using short carbon fibers coated with nickel on the surface as reinforcement and AZ91D powder as matrix metal. SEM,TEM-EDS, was used to prepare magnesium matrix composites. Tensile and dynamic thermomechanical analysis (DMA) were used to characterize the microstructure, interface structure, mechanical properties and damping properties of AZ91D magnesium matrix composites. The effects of short carbon fibers coated with nickel on the interface and damping properties of AZ91D magnesium matrix composites were studied. The results showed that carbon fiber distributed uniformly in the composites and arranged along the extrusion direction, and the wettability between carbon fiber and AZ91D matrix was improved by nickel coating. The strain spectra and G-L characteristic lines at different frequencies show that the damping mechanism of composites is not only dislocation, but also the damping mechanism of composites is changed from interfacial slip to dislocation with the increase of strain frequency. With the increase of temperature, the damping capacity of the coated carbon fiber reinforced magnesium matrix composites increases, and a damping peak appears at 250 鈩，

本文編號：2385502