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

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.

2014 ◽  
Vol 939 ◽  
pp. 90-97 ◽  
Author(s):  
Meng Wang ◽  
Yan Da Zou ◽  
Henry Hu ◽  
Gary Meng ◽  
Patrick Cheng ◽  
...  

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.


2014 ◽  
Vol 875-877 ◽  
pp. 1397-1405 ◽  
Author(s):  
G. Dinesh Babu ◽  
M. Nageswara Rao

Cast aluminum alloy 354 is used extensively for production of critical automobile components, owing to its excellent castability and attractive combination of mechanical properties after heat-treatment. With the advent of higher performance engines, there has been a steady demand to further improve the mechanical behavior of the castings made of the alloy, among others, through improvements in processing. The present study explores the possibility of improving tensile properties of the alloy by adopting certain non-conventional aging treatments. The non-conventional treatments include aging cycles similar to T6I4 and T6I6 referred to in the published literature, artificial aging in two steps instead of in single step and artificial aging preceded by various natural aging times. The results show that none of these non-conventional treatments leads to improvement of all tensile properties compared to the standard T61 treatment. Significant hardening takes place in the alloy due to natural aging. Changing the time of natural aging preceding artificial aging was found to have little effect on tensile properties.


2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Zhongchen Zhang ◽  
Michael Collins ◽  
Eric Lau ◽  
Chris Botting ◽  
Majid Bahrami

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.


2014 ◽  
Vol 875-877 ◽  
pp. 1429-1436 ◽  
Author(s):  
G. Dinesh Babu ◽  
M. Nageswara Rao

Cast aluminum alloy 354 is used extensively for production of critical automobile component, owing to its excellent castability and attractive combination of mechanical properties. With the advent of higher performance engines, there has been a steady demand to further improve the mechanical behavior of the alloy, among others, through improvements in processing. The present study explores the possibility of improving mechanical behavior and quality levels of the alloy by adopting certain non-conventional aging treatments. Quality indices Q and QC have been used for quality rating. The non-conventional treatments include aging cycles similar to T6I4 and T6I6 referred to in the published literature, artificial aging in two steps instead of in single step and artificial aging preceded by various natural aging times. The results show that none of the non-conventional treatments leads to improvement of all tensile properties compared to the standard T61 treatment. However, some specific treatments could be identified which lead to a comparable combination of tensile properties and a shade higher quality level. Increasing the time of preceding natural aging does not help in improving the tensile properties after artificial aging.


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