Role of mechanical alloying parameters on powders distribution of Al/Cu alloy and Al/Cu composite

The aim of the current study is to investigate the effect of milling time and speed on mixing properties of aluminium (Al)/copper (Cu) alloy and Al/Cu composite. Ethanol and argon gas were employed as process control agent and milling atmosphere. Mechanical alloying process by means of high-energy ball milling was performed to produce alloy and composite metal powder. This process proceeds through repeated deformation, cold welding and fracturing of powder particles mixture with a controlled fine microstructure. X-ray diffraction and particle size analyser confirmed particle size reduction of Al/Cu alloy with increasing milling time and speed. On the other hand, the addition of reinforcement particles was found to accelerate the milling process of Al/Cu composite. Scanning electron microscope micrographs revealed homogeneous distribution of powder mixture particles by mechanical alloying process at changing milling conditions

Role of mechanical alloying parameters on powder distribution of Al/Cu alloy and Al/Cu composite

The aim of the current study is to investigate the effect of milling time and speed on mixing properties of aluminium (Al)/copper (Cu) alloy and Al/Cu composite. Ethanol and argon gas were employed as process control agent and milling atmosphere. Mechanical alloying process by means of high-energy ball milling was performed to produce alloy and composite metal powder. This process proceeds through repeated deformation, cold welding and fracturing of powder particles mixture with a controlled fine microstructure. X-ray diffraction and particle size analyser confirmed particle size reduction of Al/Cu alloy with increasing milling time and speed. On the other hand, the addition of reinforcement particles was found to accelerate the milling process of Al/Cu composite. Scanning electron microscope micrographs revealed homogeneous distribution of powder mixture particles by mechanical alloying process at changing milling conditions

Investigation of layer thickness effect on the performance of low-cost and commercial fused deposition modelling printers

Rapid prototyping is one of the common technologies in additive manufacturing. The layer-by-layer mechanism of rapid prototyping allows this technology to rapidly create and print complex geometries from three-dimensional models of any objects. Fused deposition modelling is one of the common processes in rapid prototyping, and its maturity has given birth to full-scale, commercial fused deposition modelling machines, as well as low-cost, fused deposition modelling machines, which are also referred to as three-dimensional printers. This work compares the effect of layer thickness during printing on the tensile and compressive strengths of samples, for commercial and low-cost fused deposition modelling machines. Standard samples based on ASTM D638 and ASTM D695 were prepared for the tensile and compressive tests, with layer thicknesses of 0.3302 and 0.2540 mm, using acrylonitrile butadiene styrene as the printing material. From the tensile tests, specimens prepared using low-cost fused deposition modelling managed to obtain only 41.87 and 54.69% of the ultimate tensile strength of specimens prepared using commercial fused deposition modelling, for layer thicknesses of 0.3302 and 0.2540 mm. Meanwhile, from the compressive tests, specimens prepared using low-cost fused deposition modelling managed to obtain only 75.55 and 73.79% of the ultimate compressive strength of specimens prepared using commercial fused deposition modelling, for the same layer thicknesses. Ultimately, low-cost fused deposition modelling still needs more improvement in order to give better results, compared to the currently available commercial-grade fused deposition modelling printers

Brazeability and mechanical properties of Ag-Cu-Sn brazing filler metals on copper-brazed joint

This paper describes an investigation of cadmium-free silver brazing filler metals, the ternary Ag-Cu-Sn alloys. The influences of tin content on solidus and liquidus temperatures and gap filling ability of Ag-Cu-Sn alloys on copper were investigated. Microstructures of the joint and the shear strength were examined. Investigation on gap filling ability test procedure was performed according to ISO 5179-1983. The result from differential thermal analysis showed that the solidus and liquidus temperatures of the filler metals decreased with the increment of tin content in Ag-Cu-Sn. The results from the shear test showed that the brazed joint exhibited the highest strength at 10 wt-% tin content in the filler metal. The joint gaps of less than 0.10 mm were proposed when designing the brazed joint for Ag-Cu-Sn filler metals