neue Endversion16112006.indd - ULV Leoben - Montanuniversität ...

mMINING METALLURGY MATERIALS
m m
WWW.UNILEOBEN.AC.AT
Universitätslehrerverband der
Montanuniversität Leoben (ULV)
Semi-solid processing of an AlSi7 alloy
The effect of a cooling slope on the semi-solid processing of an unmodified non-grain
refined A357 AlSi7 alloy with an aim to improve as-cast properties has been investigated.
Schematic representation of experimental set-up
The following conclusions have been drawn from the results:
- Contact time, shear force and surface contact between cooling
plate and the melt are the dominant factors in the control of the
microstructure, rather than inclination angle and cooling plate
length, in the cooling slope technique.
- A 40° inclination angle gave a condition where all the factors
were optimum and the same microstructure was obtained
regardless of the initial pouring temperature for a given constant
contact time.
- Microstructures observed were non-dendritic but also not globular
in shape, the latter being characteristic of alloys with good
thixotropic properties.
Muhammad Kamran
Chair of Casting Research
at MUL since: 2003
The Author:
2000: MSc (Engneering) NED UET, Pakistan
2001-2003: University of the Punjab, Pakistan
Since 2003: PhD student at MUL
Semi-solid processing is a beneficial process due to its ability
to form a near net shape and sound product with uniform and
improved properties. The alloy was processed with pouring
temperatures of 680, 660 and 640 °C on a graphite coated
copper cooling slope, at inclination angles of 20°, 40° and 60°
for different contact lengths. These channel lengths had equivalent
contact times of 0.04, 0.09 and 0.13 seconds. The semisolid
slurry was poured into a sand mould and the resultant
microstructures compared.
Research Work:
- Casting behaviour of Al-alloys
- Semi-solid proceesing
- Anodizing of mild steel sheets
- Enrichment of Iron Ores
0.04 s
0.09 s
0.13 s
Effect of contact time on microstructure