The Role of Anodization in Naturally Cooled Heat Sinks for Power Electronic Devices

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Zhongchen Zhang ◽  
Michael Collins ◽  
Eric Lau ◽  
Chris Botting ◽  
Majid Bahrami
Keyword(s):  
Aluminum Alloy ◽  
Thermal Radiation ◽  
Electronic Devices ◽  
Heat Sinks ◽  
Al Alloy ◽  
Cast Aluminum Alloy ◽  
Power Electronic ◽  
Cast Aluminum ◽  
Die Cast ◽  
Alloy 6061

Abstract Effect of anodization on the thermal performance of naturally cooled heat sinks in power electronic devices made of die-cast aluminum alloy A380 and machined aluminum alloy 6061 was investigated experimentally and numerically. Various types of anodization were examined with different thickness of anodic aluminum oxide layer (AAO), pore size distributions, and surface coloring conditions. A customized natural convection and thermal radiation experimental chamber was built to measure the cooling capacity and heat sink temperatures. A 3D numerical model was also developed and validated against the collected data to provide more details into the contribution of the radiation heat transfer. The total emittance of the anodized samples was determined by a Fourier transform infrared reflectometer (FTIR) spectroscopy method. The results show a significant improvement in total hemispherical emissivity from 0.14 to 0.92 in anodized die-cast aluminum samples. This increase resulted in a considerable reduction in overall thermal resistance, up to 15%; where up to 41% of the total heat dissipation was contributed by thermal radiation. In spite of the rather distinguishable surface morphologies, the measurements suggested that thermal emissivity of the anodized die-cast Al A380 and Al alloy 6061 samples were in the same range.

Tensile Properties and Microstructure of Joined Vacuum Die Cast Aluminum Alloy A356 (T6) and Wrought Alloy 6061

2014 ◽  
Vol 939 ◽  
pp. 90-97 ◽  
Author(s):  
Meng Wang ◽  
Yan Da Zou ◽  
Henry Hu ◽  
Gary Meng ◽  
Patrick Cheng ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Thermal Treatment ◽  
Filler Metal ◽  
Intermetallic Phase ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
T6 Heat Treatment ◽  
Die Cast ◽  
Alloy 6061

In the present work, fusion-joining of vacuum high pressure die cast (HPDC) aluminum alloy A356 and wrought alloy 6061 by applying Gas Metal Arc Welding (GMAW-MIG) process was investigated to understand the effect of the MIG process on the microstructure and tensile behaviors of the base joined alloys (T6 Heat treatment A356 and 6061). The microstructures of the base metal (T6 heat treatment A356 and 6061), Heat Affected Zone (HAZ) and Fusion Zone (filler metal ER4043) were analyzed by Scanning Electron Microscopy (SEM) and optical microscopy. The results of tensile testing indicated that, the ultimate tensile strength (UTS) and yield strength (YS) of V-HPDC alluminium A356 subjected to T6 thermal treatment were relatively low, compared to both wrought alloy 6061 and the filler metal (ER 4043). The microstructure analysis showed that the low strengths of T6 A356 alloy should be at least attributed to the absence of the magnesium-based intermetallic phase, coarse grain structure and the presence of porosity, which resulted from the HPDC process, MIG welding and thermal treatment.

Influence of Aging Temperatures and Times on Mechanical Properties of Vacuum High Pressure Die Cast Aluminum Alloy A356

2012 ◽  
Vol 445 ◽  
pp. 277-282 ◽  
Author(s):  
Xue Zhi Zhang ◽  
Kazi Ahmmed ◽  
Meng Wang ◽  
Henry Hu
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Thermal Treatment ◽  
Tensile Properties ◽  
Intermetallic Phase ◽  
Aged Alloy ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Die Cast ◽  
Wide Range

In this study a number of thermal treatment schemes over a wide range of temperatures between 120˚ to 350˚ C and times (30 120 minutes) have been experimented in an effort to understand the effect of thermal treatment on tensile properties of vacuum die cast modified aluminum alloy A356. The results show that, the morphology of eutectic silicon has a sound effect on the tensile properties of the tested alloy. The content of magnesium-based intermetallic phases, their morphology and distribution throughout the matrix affect the mechanical properties of the aged alloy as well. The reduction in the strengths of the alloy treated at 350°C for two hours should be at least attributed partly to the absence of the magnesium-based intermetallic phase. However the presence of sufficient amount of magnesium intermetallic phase had played important role in strengthening the alloy thermally treated at 200°C for 90 minutes.

Influence of Cutting Parameters on Residual Stresses Induced by Milling in Pressure Die-Cast Aluminum Alloy Components

2000 ◽  
Vol 123 (4) ◽  
pp. 547-551 ◽  
Author(s):  
T. Berruti ◽  
G. Ubertalli
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Cast Aluminum Alloy ◽  
Feed Speed ◽  
Cast Aluminum ◽  
X Ray ◽  
Die Cast ◽  
Experimental Apparatus

Residual stress states, induced by milling in a die cast aluminum alloy component, have been determined by means of X-ray diffraction. Samples have been cut from an automotive engine sump, fabricated by pressure die-casting. The X-ray experimental apparatus has been calibrated by detecting stresses on a sample bent under imposed external deformations. Different samples (cut from the sump) have been tested after milling operations with each one characterized by different cutting speed, feed speed and depth of cut in order to evaluate their influence on the final residual stress state. Results have been analyzed taking into account surface morphologies after milling, as revealed by scanning electron microscopy.

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