CNTs-SiC_p双纳米相增强铝基复合材料的制备及其协同强化机制

发布时间：2018-05-02 22:19

  本文选题：碳纳米管(CNTs) + 纳米碳化硅颗粒(SiC_p)　； 参考：《西安理工大学》2017年硕士论文

【摘要】：碳纳米管(Carbon nanotubes,CNTs)增强铝基复合材料(Aluminum matrix composites,AMCs)因集成铝和CNTs各自的优异性能而得到广泛关注。然而CNTs分散困难以及CNTs/Al界面反应控制问题是制约其发展的瓶颈。为解决以上问题,本文提出了低能湿法混合和CNTs-SiCp双纳米相增强AMCs的新研究思路。研究首先采用低速行星球磨(Planetary Ball Milling, PBM)制备了 CNTs/Al 及 CNTs-SiCp/Al 复合粉体,利用放电等离子烧结(Spark Plasma Sintering,SPS)技术对粉体进行固化,并经热挤压(Hot Extrusion,HE)制备获得CNTs和CNTs-SiCp增强AMCs。通过热力学分析、微观组织观察、界面微观结构分析以及力学性能测试,阐明了烧结温度、CNTs含量、SiC含量及双纳米增强相对AMCs组织及性能的影响规律。CNTs增强AMCs研究结果表明:630 ℃下烧结制备的AMCs经挤压后相对密度均超过99%,达到完全致密化;CNTs含量不超过0.5 vol.%时,其在铝基体中呈现均匀单独分散状态,实际增强效果与理论值相吻合;当CNTs含量超过0.5 vol.%时,CNTs容易在局部发生聚集形成团簇,从而导致孔洞及微裂纹等缺陷,弱化CNTs的增强效果,最终降低AMCs的力学性能、延性和导电性;微观组织观察表明:CNTs能够有效地细化Al基体晶粒,并且随CNTs含量增加晶粒细化效果更为明显;界面微观结构分析表明:当烧结温度升至630 ℃时,CNTs与Al之间发生界面反应生成Al4C3,反应从CNTs外壁开始,CNTs内层仍然保持其原始管状结构;力学性能测试结果表明:随着烧结温度的升高,AMCs的抗拉强度逐渐提高。通过对CNTs-Al体系的研究确定了合适的制备工艺,明确了在此制备条件下,CNTs含量高于0.5vol%时其容易发生团聚,从而导致AMCs力学性能和导热导电性能下降,为CNTs-SiCp双纳米相增强AMCs的研究奠定了理论和实验基础。在对CNTs-Al体系研究的基础上,本文提出引入纳米SiCp作为第二增强相以促进CNTs强化效果的发挥。研究采用“超声分散-PBM-SPS-HE”相结合的工艺制备了致密的CNTs-SiCp双纳米相增强AMCs。结果表明:SiCp的加入进一步促进了 CNTs的分散,改善了 CNTs与基体之间的润湿性;SiC作为增强颗粒可以抑制晶粒的长大并阻碍位错的运动起到细晶强化和弥散强化的作用;分布于CNTs周围的SiCp可以通过钉扎作用抑制或延缓CNTs的拔出和剥离,进一步提升CNTs的强化效果,协助CNTs发挥强化作用;当两种增强粒子相互协同作用时其增强效果明显优于单一增强相,且双纳米相更有效地细化了晶粒。0.5CNTs-0.5SiCp/Al复合材料的抗拉强度达到247 MPa,相比于纯Al ( σ b =127 MPa)提升了 94%,而相比于 1.OCNTs/Al ( σ b=217 MPa)和 1.0SiCp/Al ( σ b=158 MPa)也分别有14%和56%的提升。通过界面分析,发现在CNTs与Al基体之间存在纳米级反应过渡层,显著提高了界面结合强度,使载荷可以有效地从Al基体传递至增强体,从而显著提升AMCs的强度。同时SiCp的存在也抑制了界面层的过度反应,使得AMCs强度提升的同时,能够保持和纯A1相近的延伸率(20%)和电导率(50%IACS)。CNTs-SiCp增强AMCs主要的强化机制包括载荷传递、细晶强化和弥散强化,其强化机制是CNTs和SiCp两种纳米增强相协同强化的结果。
[Abstract]:Carbon nanotube (Carbon nanotubes, CNTs) reinforced aluminum matrix composites (Aluminum matrix composites, AMCs) have been widely concerned for their excellent performance in the integration of aluminum and CNTs. However, the difficulty of CNTs dispersion and the control of CNTs/Al interface reaction are the bottlenecks that restrict its development. In order to solve the above problems, this paper proposes a low energy wet mixing and a mixture of low energy and moisture. The new research idea of CNTs-SiCp double nanometers enhanced AMCs was studied. Firstly, the composite powders of CNTs/Al and CNTs-SiCp/Al were prepared by low speed planetary ball milling (Planetary Ball Milling, PBM). The powder was cured by discharge plasma sintering (Spark Plasma Sintering, SPS). NTs-SiCp enhanced AMCs. through thermodynamic analysis, microstructure observation, interfacial microstructure analysis and mechanical properties testing, clarified the sintering temperature, CNTs content, SiC content and the influence of double nano on the relative AMCs microstructure and properties.CNTs enhanced AMCs research results showed that the relative density of AMCs prepared at 630 C was all after extrusion. More than 99%, achieve complete densification; when CNTs content is not more than 0.5 vol.%, it presents a uniform dispersion state in the aluminum matrix, and the actual enhancement effect is consistent with the theoretical value. When the content of CNTs exceeds 0.5 vol.%, CNTs is easily aggregated and formed in a local cluster, resulting in defects such as holes and micro cracks and weakens the enhancement effect of CNTs. The mechanical properties, ductility and conductivity of AMCs are reduced, and the microstructure observation shows that CNTs can effectively refine the grain of Al matrix, and the effect of grain refinement is more obvious with the increase of CNTs content. The interfacial microstructure analysis shows that when the sintering temperature rises to 630 C, the interfacial reaction between CNTs and Al generates Al4C3, and the reaction is opened from the outer wall of CNTs. In the beginning, the inner layer of CNTs still maintains its original tubular structure, and the results of mechanical properties test show that the tensile strength of AMCs increases with the increase of sintering temperature. The suitable preparation process is determined by the study of the CNTs-Al system. It is clear that when the content of CNTs is higher than 0.5vol%, it is easy to be reunion and thus leads to the AMCs force. The decline of the performance and the conductivity of thermal conductivity has laid a theoretical and experimental basis for the study of the CNTs-SiCp double nanomaterials enhanced AMCs. On the basis of the study of the CNTs-Al system, this paper introduces the introduction of nano SiCp as the second enhanced phase to promote the enhancement of the CNTs enhancement effect. The compact CNTs-SiCp double nanomaterials enhanced AMCs. results showed that the addition of SiCp further promoted the dispersion of CNTs and improved the wettability between the CNTs and the matrix, and SiC as an enhanced particle could inhibit the growth of grain and impede the motion of dislocation to enhance the crystallization and dispersion of the dislocation, and the SiCp around CNTs can pass through. The pinning effect inhibits or delays the exfoliation and stripping of CNTs, further improves the strengthening effect of CNTs and assists CNTs to exert its strengthening effect. When the two enhanced particles synergy with each other, the enhancement effect is obviously better than that of the single enhanced phase, and the double nanometers more effectively refine the tensile strength of the grain.0.5CNTs-0.5SiCp/Al composite to reach 247 MP. A, compared to pure Al (sigma B =127 MPa) increased by 94%, compared to 1.OCNTs/Al (sigma b=217 MPa) and 1.0SiCp/Al (sigma b=158 MPa) also 14% and 56%, respectively. Through the interface analysis, it was found that there was a nano reaction transition layer between the CNTs and the substrate, which significantly increased the interfacial bonding strength, so that the load could be effectively transmitted from the substrate. The strength of AMCs is greatly enhanced, and the presence of SiCp also inhibits the overreaction of the interface layer. While the strength of AMCs is enhanced, the main strengthening mechanisms of the extensibility (20%) and the conductivity (50%IACS).CNTs-SiCp enhanced AMCs, which are similar to pure A1, include load transfer, fine grain strengthening and dispersion strengthening, and its strengthening The mechanism is the result of the synergistic enhancement of two kinds of nano reinforcing phases of CNTs and SiCp.

【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

【参考文献】

相关期刊论文 前10条

1 Ziyang Xiu;Wenshu Yang;Ronghua Dong;Murid Hussain;Longtao Jiang;YongXing Liu;Gaohui Wu;;Microstructure and Mechanical Properties of 45 vol.%SiC_p/7075Al Composite[J];Journal of Materials Science & Technology;2015年09期

2 谢敬佩;王行;王爱琴;郝世明;刘舒;;真空热压SiC_p/2024Al复合材料力学性能与显微结构[J];材料热处理学报;2015年01期

3 吴文杰;王爱琴;王荣旗;谢敬佩;;SiC颗粒增强Al-Si基复合材料的国内研究进展[J];粉末冶金工业;2014年06期

4 崔照雯;刘建金;王聪聪;梁栋;高鹏;贾成厂;;碳纳米管和氧化铝颗粒在铜基复合材料中的协同作用[J];粉末冶金技术;2014年05期

5 Hansang Kwon;Marc Leparoux;Akira Kawasaki;;Functionally Graded Dual-nanoparticulate-reinforced Aluminium Matrix Bulk Materials Fabricated by Spark Plasma Sintering[J];Journal of Materials Science & Technology;2014年08期

6 刘玫潭;凌嘉辉;刘家成;洪晓松;李国强;;SiC增强Al基复合材料的制备和性能[J];半导体光电;2014年03期

7 D.Wang;B.L.Xiao;Q.Z.Wang;Z.Y.Ma;;Evolution of the Microstructure and Strength in the Nugget Zone of Friction Stir Welded SiCp/Al-Cu-Mg Composite[J];Journal of Materials Science & Technology;2014年01期

8 汤金金;李才巨;朱心昆;;碳纳米管增强铝基复合材料的界面研究进展[J];材料导报;2012年11期

9 贺毅强;;颗粒增强金属基复合材料的研究进展[J];热加工工艺;2012年02期

10 李灿民;王文芳;吴玉程;;机械合金化制备铜碳合金增强铜-石墨复合材料[J];稀有金属与硬质合金;2011年04期

相关博士学位论文 前1条

1 杨旭东;均匀分散的碳纳米管增强铝基复合材料的制备与性能[D];天津大学;2012年

，

本文编号：1835722