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.
Mechanical Impact in Disk Mill for Producing Controlled Rice Husk Particle Size by Changing Impactor Shapes and Disk Rotation Speeds
The purpose of this study was to evaluate regulation of mechanical impact (i.e. impactor sizes and shapes) on triangle, cylinder, and cube as well as disk rotation speed (from 600 to 1500 rpm) in disk mill for controlling size-reduction process. As a model of size-reduced material, rice husk was selected. The study was done by evaluating the final milling product size, which was completed by the measurement of energy impact during the milling process. Experimental results showed that the product size was controllable in the range of between 50 and 1000 μm. The impactor sizes and shapes influenced the contact diameter and area of impactor for making more materials being collided, whereas disk rotation speed led to giving more collision number (between rice husk and impactor) and increasing impact from the collision (due to less time contact during collision). This study provides an important information, which can be further generalized in the use of milling process as a tool for materials size-reduction and mechanochemical process.
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.