Analysis of the Deformability of Two-Layer Materials AZ31/Eutectic / Analiza Możliwości Odkształcania Plastycznego Materiału Dwuwarstwowego AZ31/Eutektyka

The paper present the results of physical simulation of the deformation of the two-layered AZ31/eutectic material using the Gleeble 3800 metallurgical processes simulator. The eutectic layer was produced on the AZ31 substrate using thermochemical treatment. The specimens of AZ31 alloy were heat treated in contact with aluminium powder at 445°C in a vacuum furnace. Depending on the heating time, Al-enriched surface layers with a thickness of 400, 700 and 1100 μm were fabricated on a substrate which was characterized by an eutectic structure composed of the Mg17Al12 phase and a solid solution of aluminium in magnesium. In the study, physical simulation of the fabricated two-layered specimens with a varying thickness of the eutectic layer were deformed using the plane strain compression test at various values of strain rates. The testing results have revealed that it is possible to deform the two-layered AZ31/eutectic material at low strain rates and small deformation values.

Development of novel microstructures in zirconia-toughened alumina using rapid solidification and shock compaction

A rapidly solidified alumina-zirconia eutectic material containing nanocrystalline t-ZrO2 has been synthesized. When heated, the microstructure contained a mixture of t-ZrO2 and m-ZrO2, each of which can facilitate toughening of the composite. Dynamic shock compaction was used to accelerate densification of the material, producing crack-free specimens with high green densities. After sintering to densities measuring ∼95% of theoretical, the shock-compacted specimens fabricated with unstabilized alumina-zirconia were extensively microcracked due to an overabundance of the m-ZrO2 phase. Experiments employing Y2O3 as a chemical stabilizer have shown that the extent of the phase transformation can be controlled, and the microstructure that developed in the stabilized material contained an acceptable level of the microcrack generating m-ZrO2 phase.

Electrical microcharacterization of Si-TaSi2 eutectic composites

Semiconductor-metal eutectic composites, formed by directional solidification from the melt, are composed of arrays of continuous metallic fibers contained within a single-crystal semiconductor matrix. Such composites contain rods having diameters of ≈1 μm with inter-rod spacings on the order of 10 μm. These rods form cylindrical Schottky junctions with the Si and can be used as the basis for a variety of electronic and optoelectronic devices, including photodetectors and bulk field effect transistors. Electron beam induced current (EBIC) measurements permit the determination of the depletion zone surrounding the active regions of a semiconductor material. This method has been used to examine the carrier concentration in a Si-TaSi2 eutectic composite.A portion of an oval transistor mounted on a semiconducting wafer consisting of Si-TaSi2 eutectic material with contacted rod elements was studied. The rods were selectively contacted by a deposited CoSi2 film which provided an ohmic contact to the TaSi2 rods yet formed a rectifying Schottky barrier with the Si matrix.