Zain-Ul-Abdein Muhammad, Ijaz Hassan, Saleem Waqas, Raza Kabeer, Mahfouz Abdullah Salmeen Bin, Mabrouki Tarek
Mechanical Engineering Department, University of Jeddah, Jeddah 21589, Saudi Arabia.
FMSE, GIK Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
Materials (Basel). 2017 Jul 2;10(7):739. doi: 10.3390/ma10070739.
Copper/diamond (Cu/D) composites are famous in thermal management applications for their high thermal conductivity values. They, however, offer some interface related problems like high thermal boundary resistance and excessive debonding. This paper investigates interfacial debonding in Cu/D composites subjected to steady-state and transient thermal cyclic loading. A micro-scale finite element (FE) model was developed from a SEM image of the Cu/20 vol % D composite sample. Several test cases were assumed with respect to the direction of heat flow and the boundary interactions between Cu/uncoated diamonds and Cu/Cr-coated diamonds. It was observed that the debonding behavior varied as a result of the differences in the coefficients of thermal expansions (CTEs) among Cu, diamond, and Cr. Moreover, the separation of interfaces had a direct influence upon the equivalent stress state of the Cu-matrix, since diamond particles only deformed elastically. It was revealed through a fully coupled thermo-mechanical FE analysis that repeated heating and cooling cycles resulted in an extremely high stress state within the Cu-matrix along the diamond interface. Since these stresses lead to interfacial debonding, their computation through numerical means may help in determining the service life of heat sinks for a given application beforehand.
铜/金刚石（Cu/D）复合材料因其高导热率值而在热管理应用中闻名。然而，它们存在一些与界面相关的问题，如高热边界电阻和过度脱粘。本文研究了稳态和瞬态热循环载荷作用下Cu/D复合材料中的界面脱粘现象。从Cu/20体积% D复合材料样品的扫描电子显微镜图像建立了微观尺度有限元（FE）模型。针对热流方向以及Cu/未涂层金刚石和Cu/Cr涂层金刚石之间的边界相互作用，假定了几个测试案例。观察到由于Cu、金刚石和Cr之间热膨胀系数（CTE）的差异，脱粘行为有所不同。此外，由于金刚石颗粒仅发生弹性变形，界面的分离对Cu基体的等效应力状态有直接影响。通过全耦合热-机械有限元分析表明，反复的加热和冷却循环会导致沿金刚石界面的Cu基体内出现极高的应力状态。由于这些应力会导致界面脱粘，通过数值方法计算它们可能有助于预先确定给定应用的散热器使用寿命。
