Various reactions and the in-situ formation of new phases can occur during the mechanical alloying process. In the present study, Al powders were strengthened by AlN, using the in-situ processing technique during mechanical alloying. Differential thermal analysis and X-ray diffraction studies were carried out in order to examine the formation behavior of AlN. It was found that the precursors of AlN were formed in the Al powders and transformed to AlN at temperatures above . The hot extrusion process was utilized to consolidate the composite powders. The microstructure of the extrusions was examined by SEM and TEM. In order to investigate the mechanical properties of the extrusions, compression tests and hardness measurements were carried out. It was found that the mechanical properties and the thermal stability of the Al/AlN composites were significantly greater than those of conventional Al matrix composites.

Fabrication and investigation of composite made of graphite, SiC, mullite and aluminum as the additive are the aim of this project. Aluminum acts as an anti-oxidant. SiC is a non-metallic anti-oxidant that increases composite strength. Different compositions with influent percents of aluminum have been selected to determine product specifications by XRD, SEM and STA methods. Results show that the composition of 40wt% graphite-20% SiC- 20% mullite-20% aluminum is a more robust and occurs at elevated temperatures than other graphite combustion composites.

This paper presents a new approach for analyzing the microstructure of -reinforced aluminum matrix composites from digital images. Various samples of aluminum matrix composite were fabricated by hot pressing the powder mixtures with certain volume and size combinations of pure Al and SiC particles. Microstructures of the samples were analyzed by computer-based image processing methods. Since the conventional methods are not suitable for separating phases of such complex microstructures, some new algorithms have been developed for the improved recognition and characterization of the particles in the metal matrix composites.

Vacuum degassing is essential in the preparation of RS P/M aluminum alloys to remove adsorbates and for the decomposition of hydrated- on the powder surface. Changes in the surface characteristics during vacuum degassing were investigated by X-ray photoelectron spectroscopy and temperature-programmed desorption measurement. Hydrated- decomposition to crystalline- and hydrogen desorption on the surface of argon gas-atomized aluminum powder occurred at 623 K and 725 K, respectively. This temperature difference suggests that the reaction converting hydrated- to crystalline- during vacuum degassing should be divided into the two reactions .

The new alloy1) is made from rapidly solidified Al-Ni-Zr-Ce aluminum alloy powder, and has the following unique mechanical characteristics:(1) The stress-strain curve shows a yield point; (2) The alloy shows high heat resistance; (3) Although the alloy is submicron particle diameter, it shows excellent creep resistance. We observed the micro structures of this new alloy, and it is thought that is based on the following reasons:(1) The dislocation strongly adheres to the alloy’s many crystal boundaries;(2) The added alloying elements have a small diffusion coefficient in aluminum;(3) The tiny intermetallic compound particles crystallizing at the grain boundary.

Gas release behavior from aluminum and Al 7075 alloy powders during heating in argon was investigated by in-situ gas chromatography. Water vapor, hydrogen, carbon mono-oxide were detected as individual evolution spectra against heating temperature and time. The mechanisms of water and hydrogen evolutions were studied in detail for the determination of effective degassing condition. Magnesium in the alloy powder was found to lower the hydrogen evolution temperature to enhance overall hydrogen release.

The Application of powder metallurgy (PM) aluminum structural parts is at its early growing stage, despite of some automotive applications. The market potential for PM aluminum, however, is large. Growth is expected from the market expansion of the existing applications and new applications, including the replacements of aluminum and zinc based castings and some ferrous PM automotive parts by PM aluminum. Compared to castings, PM is an efficient mass production technology. The PM aluminum is more competitive than die casting for some automotive applications. Besides weight saving leading to performance improvement, the total cost increase for aluminum PM parts is less than 15% compared to ferrous PM automotive parts. The future is promising for PM aluminum.

We successfully developed Al-Si-Transition Metal (TM) -Rare Earth (RE) Powder Metallurgy (P/M) alloy with fine microstructure, which has high strength at high temperature. This material was compacted rapidly solidified powder and directly consolidated by hot extruding or forging. Before consolidating, rapid heating was performed on powder compaction in order to keep the fine microstructure in powder state. We have also investigated the processing conditions of this new alloy by computing simulations and experiments.

New Al-based alloys with very high ultimate tensile strength were developed in high Al concentration range of 91-95 at.% for Al-Fe-Cr-Ti-M (M: Co and Mo) systems and Al-Fe-Cr-Mo-Ti-Co system by the dispersion of nanoscale quasicrystalline particles in Al phase. The effect of adding elements, M was discussed in the viewpoint of stability of super-cooled liquid state and formation ability of quasicrystalline phase. The P/M Al-Fe-Cr-Ti-M alloys with dispersed nanoscale quasicrystalline particles exhibited ultimate tensile strength of 350MPa at 573K and 200MPa at 673K.

To provide an aqueous rust inhibitor for metalworking lubricant having low toxicity and excellent rust resistance, we synthesized diester of malonic acid by three consecutive esterifications with over 98% of conversion. This substituted malonic diester could be used as an additive to mineral oil based metalworking lubricant. These metalworking lubricant compositions were showed excellent rust resistance and suitable for various metals and different metalworking processes including hot rolling and cold rolling of aluminum and aluminum alloys.

Investigation of influence the morphology of initial powder particles, application pore-formers for sintering of nickel powders and application of flux for sintering of aluminum was made. Using different methods was prepared material with size of porous in wide range size of pores (). Using the flux for gravity sintering of aluminum in air atmosphere was manufactured porous material with porosity about 45%..

Aluminum hydroxides were synthesized by a simple electrolytic reaction of aluminum plates. The aluminum monohydroxide, boehmite(AlO(OH)), was predominantly formed by the application of an electrical potential above 30V, while the mixture of the bayerite and boehmite(AlO(OH)) phases were formed below 20V. The boehmite has a clear fibrous structure which is controlled on a nanometer scale. On the contrary, the bayerite consists of the typical hourglass or semi-hourglass shaped coarse crystals as a result of an aggregation of the various crystals stacked together. The specific surface area of the boehmite nanofiber was remarkably high, reaching about .

Nanostructured aluminum powders were obtained by means of planetary ball milling with methanol as the Process Control Agent (PCA). The behavior, during milling, was considered measuring the microhardness and grain size at different milling times. Bulk near-full density samples were sintered using the Spark Plasma Sintering technology with different schedules: temperature of and , pressure of 30 MPa and 60 MPa and different modes of applying the pressure were changed in order to understand the behavior during sintering. All the samples retained their nanostructure with an increase of the grain size from about 46 up to 70-90 nm.

In order to accelerate the sintering of Al-Bronze powder covered with passive oxide film, we focused on the way to add Al-Ca fluoride consisting of and , examined the effect of the mixing rate in Al-Ca fluoride, the amount of the added Al-Ca fluoride and the sintering temperature on sintering properties of Al-Bronze powder and considered the mechanism of the sintering acceleration. Al-Bronze powder was sintered most effectively by adding Al-Ca fluoride with the mixing rate of 20mass%. If the amount of added fluoride was over 0.05mass% and the sintering temperature was over 1123K, the sintering acceleration of the Al-Bronze powder appears. Regarding the mechanism of the sintering acceleration, it was presumed that film on the surface of the Al-Bronze particles was removed in the process of the formation of gaseous AlOF by the reaction with , and the reaction was accelerated further by the presence of the liquid phase which is formed in Al-Ca fluoride.

A new approach to sintering loose packed, coarse aluminum alloy powder to full or near full density is presented. A controlled amount of water vapor is introduced into the sintering atmosphere, which disru pts the oxide film and allows metallurgical contact between particles. In addition, supersolidus liquid phase sintering is used to sinter the part to full density. Since the method is particularly applicable to uncompacted powders, it is potentially useful for sintering aluminum powder preforms manufactured by 3DPrinting and powder injection molding.

Aluminum Alloys with a content of 22 wt.-% were spray formed. This alloy features by a low density and is therefore a superior material for leightweight applications. The main problem in spray forming of this type of alloy was the occurance of high porosities. First process optimizations have been performed to decrease porosity under a certain level, so that it can be closed by an extrusion process