Rheocasting of Al-Cu Alloy A201 with Different Silver Contents

2008 ◽  
Vol 141-143 ◽  
pp. 151-156 ◽  
Author(s):  
E.P. Masuku ◽  
Gonasagren Govender ◽  
L. Ivanchev ◽  
Heinrich Möller
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Grain Boundaries ◽  
Die Casting ◽  
Solution Treatment ◽  
Cast Material ◽  
High Pressure Die Casting ◽  
Cu Alloy ◽  
Pressure Die Casting ◽  
Better Than

Rheocasting of alloys A206 and A201 was investigated in this study. Conical bars with different silver contents were produced using CSIR rheoprocess technology, together with high pressure die casting. The results showed that addition of Ag to alloy A206 increased the mechanical properties of the alloy. However, the addition of Ag also resulted in Cu-rich phases to precipitate at the grain boundaries of the as-cast material. The solution treatment used in this study was unable to dissolve all of this phase, especially in the 1.12%Ag-containing alloy. This resulted in slightly decreased mechanical properties compared to the 0.63%Ag-containing alloy. The T6 mechanical properties (strength and elongation) obtained in this study for rheocast A206 and A201 are better than those reported for permanent mould castings of alloy A206 and A201.

Fatigue Resistance of Heat Treated Aluminium High Pressure Die-Castings

2008 ◽  
Vol 41-42 ◽  
pp. 99-104 ◽  
Author(s):  
Roger N. Lumley ◽  
J.R. Griffiths
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Fatigue Strength ◽  
Die Casting ◽  
Solution Treatment ◽  
Cyclic Stress ◽  
Fatigue Properties ◽  
High Pressure Die Casting ◽  
Heat Treated ◽  
Pressure Die Casting

High pressure die-casting (HPDC) is widely used as a cost-effective way to massproduce metal components that are required to have close dimensional tolerances and smooth surface finishes. Approximately 50%, by mass, of the aluminium castings produced worldwide are made by this manufacturing route. However, HPDC components are relatively porous compared with other types of castings and so cannot usually be conventionally heat treated to improve mechanical properties. This follows because during solution treatment (e.g. at 540°C for 8h), the pores expand, resulting in unacceptable surface blisters, distortion and poor mechanical properties. Recent work within the CSIRO Light Metals Flagship has revealed a heat treatment procedure by which the problems of blistering and distortion can be avoided [1]. As a result, large improvements in strength have been achieved, as compared with the as-cast condition. One uncertainty is the behaviour of heat treated HPDCs under cyclic stress and this paper investigates the fatigue properties of a common high pressure die-casting alloy, A380 (Al-8.5Si-3.5Cu). Comparisons are made between as-cast, T4 and T6 conditions. Fatigue strength is highest for the alloy aged to a T6 temper and ratios of fatigue strength to tensile strength for the as-cast, T4 and T6 conditions are constant at a value of approximately 0.6, which is particularly high for aluminium alloys.

Effect of Excess Mg on the Microstructure and Mechanical Properties of Al-Mg2Si High Pressure Die Casting Alloys

2013 ◽  
Vol 765 ◽  
pp. 64-68 ◽  
Author(s):  
Feng Yan ◽  
Shou Xun Ji ◽  
Zhong Yun Fan
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Mechanical Performance ◽  
Eutectic Reaction ◽  
Die Casting ◽  
High Strength ◽  
Primary Phase ◽  
High Pressure Die Casting ◽  
Excess Mg ◽  
Pressure Die Casting

In this work we found that the addition of excess Mg can significantly improve the mechanical properties of pseudo-binary Al-Mg2Si alloys after high pressure die casting (HPDC). Al-8Mg2Si-6Mg alloy offered an excellent combination of high strength and reasonable ductility. Excess Mg lowers the Mg2Si content in the eutectic reaction and promotes the formation of Mg2Si as the primary phase, and this is believed to be the origin of improved mechanical performance.

Al-Mg-Si-(Cu) 6xxx Series Alloy Selection for Rheo-High Pressure Die Casting

2014 ◽  
Vol 1019 ◽  
pp. 61-66
Author(s):  
Heinrich Möller ◽  
Pfarelo Daswa ◽  
Gonasagren Govender
Keyword(s):  
High Pressure ◽  
Selection Process ◽  
Die Casting ◽  
Solution Treatment ◽  
Hot Tearing ◽  
Incipient Melting ◽  
Negative Effects ◽  
High Pressure Die Casting ◽  
Pressure Die Casting ◽  
6Xxx Series

<span><span style="font-family: Times New Roman;" face="Times New Roman"><span style="font-family: Times New Roman;" face="Times New Roman"></span></span> <p><span style="font-family: Times New Roman;" face="Times New Roman">This paper investigates the selection process of Al-Mg-Si-(Cu) 6xxx series alloys when used specifically for rheo-high pressure die casting (R-HPDC). The 6xxx series alloys have been developed as wrought alloys and certain factors must be taken into consideration when utilising them for semi-solid metal processing. It is shown that chemical composition has a significant effect on the solution treatment parameters that should be employed i.e. high Cu and excess Si levels necessitate the use of a two-step solution treatment to reduce incipient melting. This incipient melting is especially severe in areas within the component where liquid segregation occurs, which is a common phenomenon in R-HPDC. However, high Cu and excess Si levels also have advantages: it results in higher T6 strength and Cu-additions have been shown to minimise the negative effects of natural pre-ageing. Therefore, the composition of the alloy must be selected in such a way as to achieve acceptable strength without the dangers of incipient melting in liquid segregated areas. Another important modification of 6xxx series alloys used for R-HPDC that is presented is the addition of Ti to minimise hot tearing. </span></p> <p align="LEFT"><span style="font-family: Times New Roman; font-size: medium;" face="Times New Roman" size="3"> </span></p>

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