Processing of Al/SiC composites in continuous solid–liquid co-existent state by SPS and their thermal properties
Introduction
High-performance thermal management materials should have high thermal conductivities [1], [2] and low coefficients of thermal expansion (CTE) for maximizing heat dissipation and minimizing thermal stress and warping, which are critical issues in packaging of microprocessors, power semiconductors, high-power laser diodes, light-emitting diodes (LEDs), and micro-electro-mechanical systems (MEMs) [3], [4], [5], [6]. Packaging base materials well known are Cu–W [7], AlN [8], BeO [9] and Al/SiC [10]. Among these materials, particularly, Al–matrix composites containing dispersed silicon carbide (SiC) particles have received the most attention as potential candidates for a variety of uses in advanced electronic packaging. They are currently competing with established materials such as Cu/W or Cu/Mo in the electronic packaging industry [11].
High thermal conductive composites consisting of Al matrix and SiC particles have been reported by Chu et al., who fabricated a SiC-particle-dispersed Al–matrix composite by a metal infiltration technique and obtained a thermal conductivity of 163–186 W/mK for Al composites containing 50–65 vol.% SiC [12]. Al–matrix composites containing SiC particles are to date mainly fabricated by liquid metal infiltration into SiC preforms [12], [13], [14]. This process often uses Al alloys with Si and/or Mg additions to avoid the formation of interfacial products such as Al4C3, leading to a detrimental effect on the thermo-mechanical properties of the composites. When Si and Mg dissolve into the Al matrix, on the other hand, the thermal conductivity of the matrix decreases and lowers the thermal conductivity of the composites. In addition, it is difficult to make SiC particles dispersed homogeneously in the Al composite when it is fabricated by a metal infiltration technique. This is especially true when the composite contains a lower volume fraction of SiC, say less than 50 vol.%, because of the difference in packing density between SiC and Al.
Spark plasma sintering (SPS) applied as a new method for preparing high performance of Al–matrix composites containing SiC has been presented recently [15]. The main advantage of the SPS process is to fabricate various materials for relatively short sintering times at low temperatures [16], [17], [18], [19], [20], [21], [22], leading to the prevention of Al4C3 at the interface between Al and SiC. Chu et al. fabricated SiC-particle-dispersed Al–matrix composites by SPS and obtained a thermal conductivity of 224 W/mK for an Al–55 vol.% SiC composite [23]. However, pores always appear in their study as an unavoidable structure in the Al–matrix composites containing SiC fabricated in solid state by SPS, which leads to insufficient wetting between Al and SiC. This results in weak Al/SiC interfaces, especially, at high volume fractions of SiC particles. Pores considerably decrease the thermal conductivity of the Al–matrix composites due to scattering of the heat flow [24].
To fabricate high-performance thermal management materials with very high thermal conductivities and low CTEs, we have recently initiated a series of investigations to fabricate diamond-particle-dispersed metal–matrix composites [25], [26], [27], [28], [29], [30], [31], [32]. In our recent study, to improve the above-mentioned drawbacks in structural uniformity, interfacial reaction and residual pores in the composites, a new processing technique during SPS was proposed [28], [30], [31]. In our previous work, diamond-particle-dispersed Al–matrix composites were fabricated in continuous solid–liquid co-existent state during SPS, and the high relative packing density was obtained along with strong bonding between the Al matrix and the diamond particles. A thermal conductivity of 552 W/mK was obtained at a diamond volume fraction of 50 vol.% [28], [30], [31].
In the present work, Al–matrix composite containing dispersed-SiC particles was fabricated by a SPS process of continuous solid–liquid co-existent state, similar to that used for Al–matrix composites containing dispersed diamond particles. That is, in the present study, the powder mixture of SiC, pure-Al and Al–Si alloy was used for SPS processing and processing temperatures employed were lower than the melting point of Al. SPS processing parameters were optimized for the fabrication of high thermal conductive Al–matrix composite containing SiC particles. Experimental results of thermal properties and packing density were obtained from the Al–matrix composite and they are reported herein along with their microstructures observed by scanning electron microscopy.
Section snippets
Experimental procedure
According to three-dimensional Euclidean space, the maximum volume fraction of filler particles in Al–matrix composite can ideally be 74 vol.% without cavities or voids if filler particles are spherical and of mono size. Due to some experimental constraints, empirically, Al–matrix composites are commonly produced with around 50 vol.% of fillers when roughly mono-sized filler particles are used. In the present study, SiC particles (GMF-60FH2, mean particle diameter being about 110 μm, provided by
Densification of composites during fabrication by SPS
The relative packing density of the composite and the change in die temperature were investigated as a function of sintering time for various volume fractions of SiC. Some results for the packing density obtained for Al–50 vol.% SiC composite were depicted in Fig. 3. As seen in the figure, the packing density is naturally low (about 60%) prior to SPS and remains uncharged until sintering time becomes 40 s, where temperature reaches about 350 K. The packing density then increases abruptly with
Summary
Al–matrix composite containing dispersed silicon carbide particles were fabricated in a unique fabrication method where continuous solid–liquid co-existent state of the powder mixture of SiC, pure Al and Al–5mass% Si alloy was designed to use in spark plasma sintering process. The composite was well consolidated by heating in a temperature range between 798 K and 876 K for 1.56 ks. Scanning electron microscopy detected no reaction at the interface between the SiC particle and the Al matrix. The
References (38)
- et al.
Heat loss in insulated pipe the influence of thermal contact resistance: a case study
Compos Part B: Eng
(1996) - et al.
Enhancing thermal conductivity of glass fiber/polymer composites through carbon nanotubes incorporation
Compos Part B: Eng
(2010) - et al.
Local strain contours around inclusions in wire-drawn Cu/W composites
Compos Part A: Appl Sci Manuf
(1997) - et al.
The hardnesses and elastic moduli of pulsed laser deposited multilayer AlN/TiN thin films
Compos Part B: Eng
(1999) - et al.
Modeling thermal conductivity in UO2 with BeO additions as a function of microstructure
J Nucl Mater
(2009) - et al.
An experimental study on effect of thermal cycling on monotonic and cyclic response of cast aluminium alloy-SiC particulate composites
Compos Part B: Eng
(2005) - et al.
Liquid metal infiltration into ceramic particle preforms with bimodal size distributions
Curr Opin Solid State Mater Sci
(2005) - et al.
The thermal conductivity of pressure infiltrated SiCp/Al composites with various size distributions: experimental study and modeling
J Mater Des
(2009) - et al.
Effects of SiC particle size on CTEs of SiCp/Al composites by pulsed electric current sintering
Mater Chem Phys
(2006) - et al.
Processing of TiNi SMA fiber reinforced AZ31 Mg alloy matrix composite by pulsed current hot pressing
Mater Sci Eng A
(2004)
Thermal conductivity of spark plasma sintering consolidated SiCp/Al composites containing pores (Numerical study and experimental validation)
Compos Part A: Appl Sci Manuf
Thermal properties of CNT–alumina nanocomposites
Compos Sci Technol
Processing of diamond particle dispersed aluminum matrix composites in continuous solid–liquid co-existent state by SPS and their thermal properties
Compos Part B: Eng
Thermal conductivity of diamond particle dispersed aluminum matrix composites fabricated in solid–liquid co-existent state by SPS
Compos Part B: Eng
Limiting the development of Al4C3 to prevent degradation of Al/SiCp composites processed by pressure less infiltration
Compos Sci Technol
Influences of operated temperature on bending strain on cyclic motion of La–Ni alloy thin film driven by hydrogenation
J Jpn Inst Metals
Giant magnetostriction of Fe3.2Tb alloy film deposited on polyurethane rubber substrate
J Jpn Inst Metals
Development of new actuators for flapping wing flight
Mater Sci Forum
Formation of sensitive phases in metal and polymer based structural materials for health monitoring
Struct Health Monit
Cited by (75)
Effect of Al content on chemical corrosion resistance of Al/SiC composites
2023, Ceramics InternationalSolid chamber for satellite electronic modules and evaluation of its heat conduction behavior
2023, Case Studies in Thermal EngineeringThe interface reaction of SiC/Al composites by spark plasma sintering
2023, Journal of Alloys and Compounds