Norio Takatsuji

An investigation of the age hardening behavior of PM 2024Al-Fe-Ni alloys and the effect of consolidation conditions

The aging ability of two PM alloys based on 2024Al with Fe and Ni addition has been investigated by means of EDX, XRD, DSC, TEM and Vickers hardness analysis, and compared with that of the base alloy PM 2024 aluminum. Effect of consolidation temperature and powder size on the aging behavior of the 3F5N alloy was also studied. The results showed that the 3F0N alloy, PM 2024Al with 3 mass% Fe single addition, exhibited poor aging ability compared to 2024 alloy. In this alloy, the amount of solid solution Cu was found to decrease by forming Al7Cu2Fe compound during solidification, resulting in a lower amount of Cu dissolved into the α-Al matrix of the extrusions during the solution treatment. Whereas the 3F5N alloy, PM 2024Al with a 3 mass% Fe and 5 mass% Ni combined addition, showed almost the same age hardenability compared to PM 2024 alloy. Due to the addition of Ni, the amount of insoluble compound Al7Cu2Fe was decreased by the formation of Al9FeNi phase in the 3F5N alloy. Thus, more Cu could be dissolved into the matrix during the solution treatment. A quantity of GPB zone could be formed in the 3F5N alloy during the aging resulting in higher age hardenability than the 3F0N alloy. The extrusion temperature and powder size were found to affect the aging hardenability of the 3F5N extrusions. Although higher age hardenability could be obtained in the 3F5N specimen extruded from powders with the relatively larger diameter, it was found that with decreasing extrusion temperature the higher aging ability could also be obtained in the 3F5N alloy extruded from finer powders.

Effects of Friction Models, Geometry and Position of Tool on Curving Tendency of Micro-Extrusion 6063 Aluminum Alloy Pins

Micro-extrusion process is one of the micro-forming technology for fabrication of micro-parts such as micro-gear shaft for microelectromechanical system (MEMS) and micro pins for electronic parts. This paper presents the friction models effects and geometry effects on curving tendency of micro-extrusion 6063 aluminum alloy pins. Three friction models were considered: (1) Coulomb friction, (2) plastic shear friction, and (3) combined (Coulomb & plastic shear) friction. The finite element simulation was carried out and the results showed that the combined friction model accurately predicted the micro-extrusion results. Then, four tool geometry and position effects were investigated: (1) punch shift length, (2) die angle, (3) die shift length, and (4) bearing length. The finite element simulation was carried out to determine these tool geometry and position effects on the curving tendency of micro-extruded pins. The results showed that punch shift length and die angle did not affect the curving tendency. However, die shift length caused the micro-extruded pins to curve. The increase in bearing length helped straighten the micro-extruded pins.

Effect of die geometry properties on forming of micro-parts by forward-backward extrusion of 6063 aluminum alloy

The recent trend towards miniaturization of products and technology has boosted a strong demand for such metallic micro-parts with micro features and high tolerances. Conventional forming technologies, such as extrusion and drawing, have encountered new challenges at the micro-scale level due to the ‘size effects’ that tends to be predominant at this scale level. Friction is one of the predominant factors exercising strong effects in micro-forming. Previous studies varied grain size of the test pieces in order to examine size effects in micro-extrusion. In addition, the effects on the extrusion load, forming shape, as well as hardness of different grain sizes, die coatings and lubricants were compared. DLC coating has been proven effective as a die coating. Increasing grain size was effective with lubricants having high viscosity. In this study, the effect of different die Properties is compared and examined.© 2014 ASME

Application of Simulation Technology to Hollow Die Extrusion

In recent years, the application of various simulations in hot extrusion of aluminum alloys has proven useful. However, the most of them are generally applied in the field of steady metal flow conditions with solid die extrusion. In this paper, the simulation technology is applied to hollow die extrusion. Especially, the effects of the taper port-hole shapes on the extrusion pressure-stroke diagrams and the metal flows are investigated experimentally and theoretically. Taper port-hole shapes are useful for the reduction of the extrusion pressure in comparison with straight port-hole shape, because the extrusion pressure in the port-hole filling process is decreased by the reduction of the sliding friction, and the extrusion pressure in the welding chamber filling process is decreased by the reduction of equivalent strain rate in the port-hole and the welding chamber. FEM results by FEM analysis code added with special know-how show a close match with the experimental results. Therefore, we are able to predict the extrusion pressure and the metal flow through the port-hole and the welding chamber by this simulation technology.© 2007 ASME