Effect of Mill Type on Morphology of AA6013 Aluminium Powder
In conventional recycling method, metal chips are cast after pressing and melting in electric arc furnace. Material loss occurs during the recycling from liquid metal due to the several reasons. Direct recycling method which produces the aluminium powder from aluminium chips using mechanical mill can be an alternative to conventional recycling method. Thus material and energy losses, and labour cost will be reduced by direct recycling method without melting. In this study, the particle morphology of powder direct recycled from AA6013 aluminium alloy chips with cryogenic, disc and ball type grinders is investigated. Mechanical milling resulted flaky and irregular shaped AA6013 particles. It was ascertained that the chips did not break sufficiently in despite of the long duration milling mechanisms by ball mill. Cryogenic mill provides the energy required for milling mechanisms to act. Disc mill has the highest impact energy was determined. Consequently, efficiency of ball mill is lower than the efficiency of cryogenic and disc type mills. Shape factors of powders produced with ball and cryogenic mills were found greater than that of the powder produced by disc mill. Disc mill has the most efficient and effective impact energy which produces the smaller particles per minute, was determined.
New methods of aluminium and aluminium-alloy chips recycling
Abstract A technology that has been developed systematically in recent years is that of the manufacturing of sintered products with pre-determined properties. It has been demonstrated that such products can be manufactured from waste such as aluminium and aluminium-alloy chips. The method consists in the conversion of the chips directly into a finished product. The method has been applied to the production of composite materials, characterised by good strength properties at room and elevated temperature, as well as for bearing materials.
The wear properties of an alumina-aluminosilicate fibre hybrid reinforced Al-Si alloy in a lubricated condition
Abstract The wear and friction behaviour of squeeze cast Al-Si alloy and hybrid composites reinforced with alumina and aluminosilicate fibre was investigated by means of a block-on-ring (bearing steel) type wear rig. Volume loss and coefficients of friction of the hybrid metal matrix composites with 12% reinforcements were measured over a load range of 200–500 N. The experimental results show that the alumina-aluminosilicate fibre ratio exhibited a marked effect on the wear resistance of the hybrid composites. If the alumina-aluminosilicate fibre ratio is above 2:3 the hybrid composites exhibit a fairly good wear resistance, especially for higher loads in the test. However, if the ratio is below 2:3 there is a sudden increase in the volume loss at the load above 300 N. That is to say, the costly alumina fibre can be partially replaced by inexpensive aluminosilicate fibre for the production of Al-Si matrix composites with excellent wear resistance. Also discovered experimently is that the coefficient of friction for the hybrid composites was higher than that of the unreinforced Al-Si alloy, and that it illustrated little variation with alumina-aluminosilicate fibre ratio.