【摘要】：碳納米管(CNTs)因其高強度、高模量、高韌性等優(yōu)異的力學性能而被認為是最具潛力的增強體。近年來,以CNTs為增強體制備復合材料引起了廣大科研工作者濃厚的興趣,但是對CNTs-Ti基復合材料的研究尚處于初級階段。研究表明,加入少量的CNTs可以有效地增強材料的強度。然而,CNTs與Ti在高溫下極易發(fā)生反應生成TiC,雖然TiC也可以起到第二相強化的作用,但這勢必會破壞CNTs的完整性,降低其力學性能、從而影響其增強效果。為了達到既抑制TiC的生成又獲得高強度復合材料的目的,本次實驗采用低溫高壓的燒結工藝制備CNTs-Ti復合材料。放電等離子燒結技術(SPS)是近年來發(fā)展起來的一種新型快速燒結技術,能夠滿足低溫高壓的燒結要求。本文采用SPS燒結技術制備CNTs-Ti基復合材料,研究了燒結溫度及CNTs含量對復合材料相對密度、顯微組織及力學性能的影響。本研究共設定了四個燒結溫度點(400℃、450℃、500℃、550℃)和五種不同的成分(CNTs含量分別為0.2 wt%、0.4 wt%、0.6 wt%、0.8 wt%、1.0wt%)。所有實驗其余燒結參數如下:初始壓力1MPa、燒結壓力為300MPa、保溫時間為5min、升溫速率為60K/min。研究結果表明:燒結溫度為550℃,CNTs含量為1.0wt%的復合材料在燒結過程中并無TiC生成;復合材料的相對密度、顯微硬度、抗拉強度及延伸率與動態(tài)屈服強度均隨著燒結溫度的升高而逐漸增大,在550℃時達到最大;CNTs含量對復合材料的相對密度無明顯影響;復合材料的顯微硬度、抗拉強度及動態(tài)屈服強度均隨CNTs含量的增加呈現先增加后減小的變化趨勢,當CNTs含量為0.4 wt%時,復合材料的抗拉強度及動態(tài)屈服強度均達到最大;復合材料的延伸率及晶粒尺寸則隨著CNTs含量的增加而逐漸減小。當燒結溫度為550℃,CNTs含量為0.4wt%時,復合材料具有最佳的綜合力學性能,致密度為99.35%,抗拉強度為547MPa,延伸率為26%,硬度為2226MPa,動態(tài)流變應力為1033MPa,吸收功為417KJ/m3。這一成果為以后的CNTs-Ti基復合材料的研究奠定了一定的基礎。
[Abstract]:Carbon nanotubes (CNTs) are considered the most potential enhancements for their excellent mechanical properties, such as high strength, high modulus, high toughness and so on. In recent years, the preparation of composite materials with CNTs has aroused great interest of the researchers, but the research on CNTs-Ti based composites is still in the primary stage. CNTs can effectively enhance the strength of the material. However, CNTs and Ti are easily reacted to produce TiC at high temperature. Although TiC can also play the role of second phase intensification, it will destroy the integrity of CNTs, reduce its mechanical properties, and affect its enhancement effect. In order to achieve the inhibition of the generation of TiC and the high strength composite material The purpose of this experiment is to prepare CNTs-Ti composites with low temperature and high pressure sintering process. Discharge plasma sintering (SPS) is a new rapid sintering technology developed in recent years. It can meet the requirements of sintering at low temperature and high pressure. This paper uses SPS sintering technology to prepare CNTs-Ti matrix composites, and studies the sintering temperature and CNTs. The effect of the content on the relative density, microstructure and mechanical properties of the composites. Four different sintering temperature points (400 C, 450, 500, 550) and five different components were set in this study (CNTs content was 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, 1.0wt%). The other sintering parameters were as follows: initial pressure 1MPa, sintering pressure 300M Pa, the heat preservation time is 5min and the heating rate is 60K/min., the results show that the composite materials with sintering temperature of 550 C and CNTs content 1.0wt% have no TiC formation during the sintering process, and the relative density, microhardness, tensile strength and elongation and dynamic yield strength of the composite gradually increase with the increase of sintering temperature, at 550 degrees C. The content of CNTs has no obvious effect on the relative density of the composite. The microhardness, tensile strength and dynamic yield strength of the composite increase first and then decrease with the increase of CNTs content. When the content of CNTs is 0.4 wt%, the tensile strength and dynamic yield strength of the composite material are all maximum; the composite material is the most important. The elongation and grain size decrease gradually with the increase of CNTs content. When the sintering temperature is 550 C and CNTs content is 0.4wt%, the composite has the best comprehensive mechanical properties, the density is 99.35%, the tensile strength is 547MPa, the elongation is 26%, the hardness is 2226MPa, the dynamic rheological stress is 1033MPa, the absorption work is 417KJ/m3. this 10%. The results laid a foundation for the future research of CNTs-Ti matrix composites.
【學位授予單位】：北京理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB33

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本文編號：2163464