The Effects of Cu Content on Microstructure and Mechanical Properties of Thixoformed A319 Aluminium Alloys

2014 ◽  
Vol 548-549 ◽  
pp. 237-241
Author(s):  
M.S. Salleh ◽  
M.Z. Omar ◽  
J. Syarif ◽  
K.S. Alhawari ◽  
M.N. Mohammed
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloys ◽  
Scanning Calorimetry ◽  
Fraction Liquid ◽  
Cu Content ◽  
Cooling Slope ◽  
Microstructure And Mechanical Properties ◽  
A319 Alloy ◽  
Cooling Slope Casting ◽  
Effect Of Copper

The effect of copper contents on the microstructure and mechanical properties of A319 aluminium alloy in thixoformed conditions was investigated. The results showed that the addition of 1 wt. % and 2 wt. % copper to A319 alloy reduced the fraction liquid sensitivity and enlarged the working window temperature. Based on the differential scanning calorimetry (DSC) data, the curve of the fraction liquid versus temperature was constructed for each alloy, indicated the temperatures corresponded to the fraction liquid of 30% and 50%. It was found that the working window temperature for A319 alloy of 7 oC increased to 12 °C when 2 wt. % copper was added, while the sensitivity decreased from 0.027 °C-1 to 0.016 °C-1.The alloy feedstocks produced by cooling slope casting were thixoformed successfully at 40% fraction liquid. The thixoformed A319 alloys attained a hardness level as high as 118.2 ± 2.5 HV when 2 wt. % copper was added.

MICROSTRUCTURAL INVESTIGATION AND MECHANICAL PROPERTIES OF THIXOFORMED AL-6SI-XCU-0.3MG ALLOYS

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Mohd Shukor Salleh ◽  
Nurul Naili Mohamad Ishak ◽  
Saifudin Hafiz Yahaya
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Intermetallic Phase ◽  
Dendritic Microstructure ◽  
Microstructural Investigation ◽  
Cu Content ◽  
Cooling Slope ◽  
Cooling Slope Casting

In this study, the effect of different amounts of copper (CU) on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg (x= 3, 4 and 5, mass fraction, %) were investigated. The alloys were prepared via cooling slope casting technique, before there were thixoformed using compression press. All of the alloys were then characterized using optical microscope (OM), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results obtained revealed that cooling slope casting produced a non-dendritic microstructure and the intermetallic phase in the thixoformed samples was refined and evenly distributed. The results also revealed that as the Cu content in the alloy increases, the hardness and tensile strength of the thixoformed alloys also increase. The hardness of thixoformed Al-6Si-3Cu was 104.1 HV while the hardness of Al-6Si-5Cu alloy was increased to 118.2 HV. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed alloy which contained 3wt.% Cu were 241 MPa, 176 MPa and 3.2% respectively. The ultimate tensile strength, yield strength and elongation to fracture of the alloy that contained 6wt.% of Cu were 280 MPa, 238 MPa and 1.2% respectively. The fracture surface of the tensile sample with lower Cu content exhibited dimple rupture while higher Cu content showed a cleavage fracture.

EFFECTS OF RHEOCASTING AND THIXOFORMING ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A356 ALUMINIUM ALLOY

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
M. Samsudin ◽  
M.Z. Omar ◽  
S. Abdullah
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloy ◽  
Room Temperature ◽  
Liquid Fraction ◽  
Casting Machine ◽  
Cooling Slope ◽  
Microstructure And Mechanical Properties ◽  
Ram Speed ◽  
Cooling Slope Casting ◽  
Steel Mould

This paper presents the changes in mechanical properties and microstructure of aluminium alloy A356 that undergoes cooling slope casting. The alloy was cut into small cubes with an estimated weight of 400g before it was heated in a crucible induction casting machine. The temperature was set to 880 oC with a heating rate of 15 oC per min. Then, the metal was cooled to 620 oC until it turns to a semisolid, before pouring into a stainless steel mould through a 250 mm long and 60o cooling slope before it was cooled to room temperature. For the thixoforming experiments, the liquid fraction was between 30% and 50%, with various semisolid temperatures (583 oC-585 oC). The ram speed and die temperature were 85 mm/s and 200 oC, respectively. The microstructure and mechanical properties of rheocast feedstock in T6 condition were determined and compared with the metal without any heat treatment, rheocast and thixoformed alloy. It was found that thixoformed metal had the highest ultimate tensile and yield strength with reduced ductility. The microstructures are rosette, near globular and spherical, and were obtained in rheocast and thixoformed alloys, respectively. The α-Al grains were larger at higher semisolid temperatures.

Effect of Pouring Temperature and Cooling Slope Length on Microstructure and Mechanical Properties of Rheocast A319 Aluminium Alloy

2014 ◽  
Vol 699 ◽  
pp. 251-256 ◽  
Author(s):  
M.S. Salleh ◽  
M.Z. Omar ◽  
J. Syarif ◽  
M.N. Mohammed ◽  
K.S. Alhawari
Keyword(s):  
Aluminium Alloys ◽  
Fuel Efficiency ◽  
Dendritic Microstructure ◽  
Slope Length ◽  
Cooling Slope ◽  
A319 Alloy ◽  
Materials Used ◽  
Engine Blocks ◽  
Cooling Slope Casting ◽  
Primary Aluminium

Aluminium alloys are among the most prominent and well known materials used in automotive industries. Nowadays, many vehicles used aluminium engine blocks instead of cast iron to improve fuel efficiency. Among cast aluminium alloys, A319 grade alloys are normally used in automotive industries due to a combination of good fluidity and mechanical strength. In this study, A319 cooling slope rheocasting billets were produced in order to obtain near spherical morphology of primary aluminium phase. The change in the α-Al morphology upon the cooling slope casting was remarkable and the dendritic microstructure was almost replaced by α-Al globules and rosettes. The rheocasting billets were prepared for tensile testing at room temperature. It is found that, the yield strength and elongation of cooling slope rheocasting billets is higher than those from as-cast A319 alloy.

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