Fabrication of Carbon Fiber Oriented Al-Based Composites by Hot Extrusion and Evaluation of Their Thermal Conductivity

Abstract

New heatsink materials having higher thermal conductivities have recently been required due to the recent rapid improvements in performance of the central processing unit, CPU, with increasing heat generation from computer devices. As an alternative material to conventional heatsink materials such as Al and Cu, composites containing carbon fibers have recently been gaining much attentions because of their extremely high thermal conductivity. However, the carbon fiber exhibits high thermal conductivity only in its longitudinal direction. Therefore, it is essential to control the orientation of the carbon fibers in the composite materials. In the present study, hot extrusion of a powder fiber mixture is applied to realization of unidirectional array of carbon fibers in Al matrix, and the effects of volume fraction of carbon fiber on the thermal conductivity of the carbon fiber oriented Al based composite have been investigated. It has been demonstrated that the carbon fibers are unidirectionally oriented in the extrusion direction, and consequently, the thermal conductivity in this direction increases with the increase in volume fraction of the carbon fiber. For the composites with more than 30 vol carbon fiber, the addition of Al Si alloy powder or the application of the spark plasma sintering, SPS, before extrusion was found to be effective for improving the sinterability of the powder fiber mixture.

Creation of anti-frost micro-plastic texture surfaces enhancing thermal conductivity by carbon black containing in polyvinyl chloride

“…% CB, sharp protrusions of CB are observed. For instance, carbon fiber a diameter of 10 μm included in pure Al have been reported to have a thermal conductivity of 0.323 kW/mK (Tokunaga et al, 2016) when the carbon fiber existed around 40 vol. %.…”

Metal Matrix Composite in Heat Sink Application: Reinforcement, Processing, and Properties

“…Aluminum, being lighter, has a high specific thermal conductivity, which makes it the leading matrix material for heat sink composites in automotive and aerospace electronics, and also in portable electronic devices [ 101 , 102 , 103 , 104 , 105 , 106 ]. However, the high coefficient of thermal expansion (~23 × 10 −6 K −1 ) of aluminum is compensated by reinforcement with carbides (SiC [ 33 , 101 , 107 , 108 , 109 , 110 , 111 , 112 ], B 4 C [ 105 ]), nitride (BN [ 107 , 113 ], Si 3 N 4 [ 114 ], AlN [ 111 , 115 ]), oxides (Al 2 O 3 [ 107 ]), diamond [ 102 , 106 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 ], graphite flakes [ 68 , 127 , 128 , 129 ], and carbon fibers [ 39 , 130 , 131 , 132 , 133 ].…”

“…A in-plane thermal conductivity and coefficient of thermal expansion of 258 Wm −1 K −1 and 7.09 × 10 −6 K −1 , respectively, were reported. Tokunaga et al [ 133 ] achieved a thermal conductivity of 323 Wm −1 K −1 with 40 vol% reinforcement of carbon fibers in aluminum matrix with Al-12.2 mass% Si alloy (10 vol%). Pei et al [ 132 ] reinforced carbon fibers into AA6063 matrix.…”

“…Copper matrix composites reinforced with (30–80 vol%) diamond particles were preferentially consolidated by SPS [ 45 , 54 , 57 , 61 , 62 , 63 , 67 , 90 , 92 ]. It was also used in the consolidation of CNT (0–15 vol%)-reinforced Cu [ 74 ], and Al [ 137 ] matrix composites and in carbon fiber (30 vol%) [ 133 ] and graphite flakes (50 vol%) [ 129 ] reinforced AMCs as well. The pulse plasma sintering (PPS) was used in the sintering of copper matrix composites reinforced with 50 vol% diamond particles [ 50 , 56 , 58 ].…”

Estimation of Effective Thermal Conductivity of Copper-Plated Carbon Fibers Reinforced Iron-Based Composites by 2D Image Analysis

“…16,17) However, the production efficiency of the two methods is extremely low, the bonding force between the C f and matrix is small, and the direction of the C f is difficult to control. Matsuura et al 18,19) used hot extrusion to change the orientation of C f in Composites through mechanical extrusion to improve the TC of the composite. Considering the cost and convenience of the experiment, this experiment adopted the method of hot rolling to control the distribution of C f in the composite.…”