In solid‐state recycling, chip morphology related parameters such as size fraction, surface topography and geometry are important factors in resulting final bond strength. Analyzing deformation parameters together with chip morphology can provide an insight of which factors are very crucial to mechanical performance of the recycled chips. This work investigates the effect of chip morphology and in particular chip roughness and surface area on the weld strength of direct recycled aluminum chips. The influence of these factors were compared with the influences of temperature and pressure. Full factorial design with center point analysis was adopted to rank the factors effects. The chips of AA6061 were cold compacted at 10 tonnes and subsequently hot forged through the dog bone shape‐die at different operating regimes. The elastic and plastic behavior and ultimate tensile strength of the hot‐pressed samples were analyzed and compared. It was found that temperature and pressure are more important to be controlled rather than the chip morphology. Low chip roughness incorporated with high temperature revealed a very significant influence over the weld strength attainment. Regardless of the chip roughness, the bond strength can still be maximized when other deformation factors were controlled within the minimum specified limit.

This paper present the effect of drilling parameter such as spindle speed, feed rate and drilling tool size on material removal rate (MRR), surface roughness, dimensional accuracy and burr. In this work, a study on optimum drilling parameter for HSS drilling tool in micro-drilling processes in order to find the best drilling parameter for brass as a workpiece material. Micro drilling experiment with 0.5 mm to 1.0 mm drill sizes were performed by changing the spindle speed and feed at three different levels. The results were analyzed using microscope and surface roughness device. Comparatives analysis has been done between surface roughness, MRR and accuracy of drilled holes by experimentation. From the result, the surface roughness are mostly influenced by spindle speed and feed rate. As the spindle and feed rate increases, the surface roughness will decrease. The tool diameter gives less influence on the value of surface roughness. The value of MRR is decreased when the tool diameter, spindle speed and feedrate are decreases. As drilling tool diameter, feedrate and spindle speed increase the dimensional accuracy of drilled hole will decrease. The increment of spindle speed and feed rate value mostly will affect the tool wear and size of burr on the edge of drilled holes.

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Metal matrix composites spur the possibility of advancing typical monolithic material properties. Offering great strength, lightweight and being able to withstand high temperatures are the main behaviours of the metal matrix composite. To that extent, many practitioners in either automotive or aerospace industries employed metal matrix composite in most of the critical parts. Forming metal matrix composite via solid state processing is considered innovative, as most of the metal matrix composite forming process took place either in liquid or gaseous processing. This paper studied in varying alumina amount from 1 to 5 wt % that had been introduced to recycled aluminium chip employing hot press forging. Aluminium chip was obtained by milling AA6061‐T6 bulk to a certain parameter. The medium size chips were cleaned, dried and mixed with alumina particles before being poured into a closed‐die mould. The main responses investigated were ultimate tensile strength and elongation to failure. Out of all fractions, 2 wt % of alumina ousted the other by significantly strengthening the composite and ductility, slightly better than the standard value. Further addition of alumina would enhance the composite strength, but in contrary, it also could threaten the material performance.

Direct hot extrusion is an alternative process for recycling aluminium without melting the scrap. It utilizes low energy and is environmental friendly. This paper reports the microhardness and microstructure of aluminium alloy chips when subjected to various settings of preheating temperature and preheating time in hot extrusion process. Three values of preheating temperature are taken as 450 °C, 500 °C, and 550 °C. On the other hand, three values of preheating time were chosen (1 h, 2 h, 3 h). The influences of the process parameters (preheating temperature and time) are analyzed using design of experiments approach whereby full factorial design with center point analysis are adopted. The total runs are 11 and they comprise of two factors of full factorial design with 3 center points. The responses are microhardness and microstructure. The results show that microhardness increases with the decrease of the preheating temperature. The results also show that the preheating temperature is more important to be controlled rather than the preheating time in microhardness analyses. The profile extrudes at 450 °C and 1 hour has gained the optimum microhardness and it can be concluded that setting temperature at 550 °C for 3 hours results in the highest responses for average grain sizes in analysis of microstructure.