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Titanium aluminide (TiAl) is an intermetallic compound possessing excellent high-temperature performance while having significantly lower density than nickel-based superalloys. This paper presents preliminary results of experiments aimed at processing TiAl via the electron beam melting (EBM) process. Two processing routes are explored. The first uses prealloyed powder, whereas the second explores controlled reaction synthesis. Issues such as processing parameters, vaporization of alloying elements, microstructure, and properties are discussed.

Purpose -Optimization techniques can be used to design geometrically complex components with a wide variety of optimization criteria. However, such components have been very difficult and costly to produce. Layered fabrication technologies such as electron beam melting (EBM) open up new possibilities though. This paper seeks to investigate the integration of structural optimization and direct metal fabrication process. Design/methodology/approach -Mesh structures were designed, and optimization problems were defined to improve structural performance. Finite element analysis code in conjunction with nonlinear optimization routines were used in MATLAB. Element data were extracted from an STL-file, and output structures from the optimization routine were manufactured using an EBM machine. Original and optimized structures were tested and compared. Findings -There were discrepancies between the performance of the theoretical structures and the physical EBM structures due to the layered fabrication approach. A scaling factor was developed to account for the effect of layering on the material properties. Practical implications -Structural optimization can be used to improve the performance of a design, and direct fabrication technologies can be used to realise these structures. However, designers must realize that fabricated structures are not identical to idealized CAD structures, hence material properties much be adjusted accordingly. Originality/value -Integration of structural optimization and direct metal fabrication was reported in the paper. It shows the process from design through manufacturing with integrated analysis.

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The increase in demand for refrigeration globally in the field of airconditioning , food preservation, medical services, vaccine storages, and for electronic components temperature control led to the production of more electricity and consequently an increase in the CO2 concentration in the atmosphere which in turn leads to global warming and many climatic changes. Thermoelectric refrigeration is a new different because it can reduce the use of electricity to produce cooling effect and also meet today's energy challenges. Therefore, the need for thermoelectric refrigeration in developing countries is very high where long life and low maintenance are needed. The objectives of this study is to develop a working thermoelectric refrigerator to cool that utilizes the Peltier effect to cool and maintain a selected temperature range of 5 0C to 25 0C. The design requirements are to cool this volume to temperature within a short time and provide retention of at least next half an hour. The design and development of thermoelectric refrigerator for required applications are presented.