Improvement of Al-6061 alloys mechanical properties by controlling processing parameters
— this paper discusses the effect of casting processing parameter on the mechanical properties of Aluminum alloy 6061 companied with Al 2 O 3 and Si C P. The specimens were poured in two different mold types one of steel and the other of graphite. These two types have a wide range of cooling rate; steel has fast cooling rate whereas graphite has slow one. In order to investigate this effect, and the alloying elements participation the specimens were taken from three different positions in the mold; top, middle and bottom. The mechanical wear, hardness and microstructure examination were performed. The results showed that wear rate and hardness increase in case of specimen poured in steel mold. This increasing due to fast cooling rate which make refining of the grain size of aluminum alloys. Whereas, their mechanical properties decreased when using graphite molds. In contrast of this result, ductility is increased. This is attributed to that graphite has slow cooling rate (heat dissipate is low) which make enlargement to the grain size of aluminum alloy and the graphite is also solid lubricate playing as interactive lubricate which is main reason to decrease the wear rate.
Wear Properties of Hot Extruded Aluminum Powder Compacts
Aluminum powder compacts have low wear
resistance due to the reduction in ductility. The ductility enhances using the metalwork
technology like the hot extrusion process. The wear test is done using pin on disc machine for all hot extruded aluminum ...
Effect of isothermal heat treatment on the creep behaviour of an AlTiCp composite
Abstract The microstructure and steady state creep of a powder metallurgy processed Al-20 vol.% TiCp composite have been characterized in as-extruded and in heat-treated conditions (heat treated at 893 K for 24, 96 and 171 h). While as-extruded composite contains only TiC particles, the composite after heat treatment has Al3Ti and Al4C3 particles in addition to TiC. The steady state creep data of the composite show that the creep strength increases substantially after heat treatment. The increase in the creep strength is proportional to the duration of heat treatment up to a certain level and is attributed to the total increase in the volume fraction of particles. The apparent stress exponent and apparent activation energy for steady state creep of the as-extruded composite are very high, 16 and 259 kJ mol−1 respectively, like other aluminium matrix composites. The steady state creep data of heat-treated composite exhibit curvature indicating the possibility of a transition in the creep mechanism. The present results demonstrate that the creep strength of Al-TiC composite can be tailored to suit the requirement by choosing a proper heat treatment. A comparison of the creep strength of various aluminium matrix composites indicates that the Al-TiCp composite after heat treatment has the best creep strength.