Optimized choice of material for two principally different types of PM components is presented. The first is characterized by high stresses in areas with high stress concentrations (for example synchronizer hubs with very sharp notches, typically <0.25mm in the pre-synchronizer slot and the inner splines). The second type has slightly larger notch radii (small spur gears and sprockets with typically notch radii between 1- 3mm). Diffusion alloyed materials are well suited for sharp notch components. Pre-alloyed materials are also well suited for applications with sharp notches if compressive residual stresses in the notch roots are created by appropriate process control. A free choice of material is available for components with the larger notch radii.

is an extremely high alloyed PM material containing about 20 to 35 wt.% titanium based carbides. Such materials are designed to achieve a high wear resistance, but the high volume fraction of hard phases causes a comparable low ductility in case of tensile loading. In the present study the mechanical properties of different Ferro-Titanit grades (variations in chemical composition and in heat treatment) were investigated by means of tensile tests. The mechanical properties and the fracture behaviour will be related to the chemical composition, the heat treatment and the microstructure.

Ti-Zr-Ni coatings deposited by low vacuum plasma spray technique consisted of nanometer-sized 1/1 cubic approximant and TiZrNi Laves phases as well as a low volume fraction of phase. The shift of composition during deposition of the quasicrystalline powders and the presence of phases are believed to be responsible for the reduced corrosion performances evaluated by means of electrochemical tests in a Hanks' Balance Salt Solution at .

The particle reinforced composite fabricated by a powder-in sheath rolling (PSR) method was severely. deformed by the accumulative roll-bonding (ARB) process. The ARB process was performed up to 8 cycles at ambient temperature without lubricant. The ARBed composite exhibited an ulbricant. grained structure similar to the other ARBed bulky materials. Tensile strength of the composite increased gradually with the number of ARB cycles, but from the 6th cycle it rather decreased slightly. These characteristics of the composite were somewhat different from those of Al powder compact fabricated by the same procedures. The difference in microstructure and mechanical properties between Al powder compact and the composite was discussed

The effect of Cu content on microstructure and mechanical properties of nano-sized Cu dispersed nanocomposites was investigated. The nanocomposites with Cu content of 2.5 to were prepared by reduction and hot-pressing of powder mixtures. The nanocomposites with Cu content of 2.5 and exhibited the maximum fracture strength of 820MPa and enhanced toughness compared with monolithic . The strengthening was mainly attributed to the refinement of matrix grains. The toughening mechanism was discussed by the observed microstructural feature based on crack bridging

In this paper, fly ash was investigated as a basic Si-Al ingredient of geopolymer. Based on compressive and flexural strength, the replacement percentage of fly ash and 3 types of curing regimes were studied to obtain the optimum synthesis condition. The results showed that geopolymer containing 30% fly ash that was prepared at 80˚C for 8 hours, exhibited high mechanical strength. The compressive and flexural strength of the fly ash based geopolymer were 32.2 and 7.15MPa, respectively. In order to investigate the durability behavior of fly ash based geopolymer concrete, CI permeability, freeze-thaw tests were also carried out. The measured results indicated that fly ash based gopolymer concrete had 2.63 times lower coefficient of chloride-ion diffusion and could withdraw 2.2 times more freeze-thaw cycles as compared to Portland concrete with the same compressive strength.

In order to fabricate complex-shaped polycrystalline ceramics by sintering, organic binders are usually pre-mixed with ceramic powders to enhance the formability during the shape forming process. These organic binders, however, must be eliminated before sintering so as to eliminate the possibilities of poor densification and unusual grain growth during sintering. The present work studies the effect of binder addition on grain growth behavior during sintering of piezoelectric ceramics. The microstructures of the sintered samples were examined for various heating profiles and debinding schedules of the binder removal process. Addition of Polyvinyl butyral(PVB) binder promoted abnormal grain growth especially in incompletely debinded regions. Residual carbon appears to change the grain shape from comer-rounded to faceted and enhance abnormal grain growth