文章信息/Info

Title:

Study on Thermal Conductivity of Magnesium Matrix Composites Reinforced by Carbon Nano-tubes

文章編號:

1674-3962(2020)01-0012-07

作者:

杜文博; 侯江濤; 孟繁婧; 李淑波

（北京工業大學 材料科學與工程學院，北京，100124）

Author(s):

DU Wenbo;  HOU Jiangtao;  MENG Fanjing;  LI Shubo

(College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China)

關鍵詞:

碳納米管; 鎂合金; 復合材料; 導熱性能; 顯微組織

Keywords:

Carbon Nano-tubes;  Magnesium Alloys;  Composites;  Thermal Conductivity;  Microstructures

分類號:

TG146.22；TB333

DOI:

10.7502/j.issn.1674-3962.201907023

文獻標志碼:

A

摘要:

鎂及其合金是目前最輕的金屬結構材料，合金化雖然提升了鎂合金的力學性能，但導致其導熱性能嚴重下降，限制了鎂合金的應用。碳納米管（CNTs）因具有優異的力學、熱學等性能，是最理想的增強體之一，可以用于改善鎂合金的力學性能和熱學性能。采用粉末冶金法分別以純Mg、Mg-9Al合金、Mg-6Zn合金為基體制備了不同CNTs含量的鎂基復合材料，利用光學顯微鏡、掃描電子顯微鏡、透射電子顯微鏡對復合材料微觀組織、基體與增強體界面及析出相進行表征，并對復合材料的拉伸性能和熱學性能進行測試。研究結果表明，當CNTs質量分數不超過1.0%時，可提高純鎂基復合材料的導熱性能，力學性能僅有稍微降低；將CNTs添加到Mg-9Al合金中，可以促進納米尺度β-Mg17Al12相在CNTs周圍析出，降低了Al在Mg基體中的固溶度，使CNTs/Mg-9Al復合材料的導熱性能有所提高。此外，在CNTs/Mg-6Zn復合材料界面處存在C原子和Mg原子的相互嵌入區，這種嵌入型界面不僅有利于復合材料力學性能的提高，也使CNTs起到加速電子移動的“橋”的作用，有利于該復合材料熱導率的提高。當CNTs質量分數為0.6%時，CNTs/Mg-6Zn復合材料具有較為優異的熱學性能和力學性能，其熱導率為127.0 W/(m·K)，抗拉強度為303.0 MPa，屈服強度為204.0 MPa，伸長率為5.0%。

Abstract:

Currently, magnesium (Mg) and its alloys are the lightest structural metallic materials. Although the mechanical properties of Mg alloys can be improved by adding alloy elements, it causes a significant reduction of thermal property. Therefore, the application of Mg alloys is limited. Carbon nano-tubes (CNTs) are one of the most ideal reinforcements due to their excellent mechanical and thermal properties. They can be used to improve the mechanical and thermal properties of Mg alloys. Using pure Mg, Mg-9Al and Mg-6Zn as matrixes, the magnesium matrix composites with various CNTs contents were fabricated via the powder metallurgy method. The microstructures , interfaces between CNTs and matrix as well as precipitated phases of composites were characterized by OM, SEM and TEM. Moreover, the mechanical and thermal properties of composites were measured. Results indicate that the thermal conductivities of CNTs/Mg composites are enhanced with CNTs content less than 1.0wt%, while their mechanical properties only have a slight decrease. As CNTs are added into Mg-9Al alloy, a few nano-sized β-Mg17Al12 phases precipitates around CNTs. It has reduced the solid solubility of Al atom in Mg matrix, so that the thermal conductivity of CNTs/Mg-9Al composite increases. In CNTs/Mg��6Zn composites, there is an area where C and Mg atoms have embedded in each other at the interface. On the one hand, the embedding area coud improve the mechanical properties of CNTs/Mg-6Zn composite. On the other hand, it could make CNTs as a “bridge” to accelerate the movement of electrons, accordingly increasing the thermal conductivity of composites. When the CNTs content is 0.6wt%, CNTs/Mg-6Zn composite has relatively excellent thermal and mechanical properties. Its thermal conductivity is 127.0 W/(m·K), and its ultimate tensile strength is 303.0 MPa, tensile yield strength is 204.0 MPa and elongation is 5.0%.