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The strain hardening exponent and strength coefficient of the Ramberg-Osgood flow rule are required for the accurate design analysis of the materials of aeroengine components. A direct method of deriving these parameters involves the processing of the complete raw data of tensile testing as per ASTM E-646. More often, a first design effort of aeroengine components is made using catalogue data, as the evaluation of material tensile properties is a time-consuming process that takes place concurrently. Catalogue-supplied data on the monotonic loading typically contains elastic modulus, 0.2% proof stress, and ultimate tensile stress along with other data for various temperatures. A methodology was evolved in this work to construct the Ramberg-Osgood flow rule with these three parameters and was validated with laboratory test results and published data through a comparison with ASTM E-646. The strain hardening exponents and strength coefficients were established for a family of aeroengine metallic materials for various temperatures, which can serve as a first design effort input.

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Ti-6Al-4V alloys are perfectly suited for fan compressor blade material in advanced aero engine components due to outstanding resistance to corrosion and specific strength was high in both room temperature and elevated temperature. For autogeneous welding of thin sheets of Ti-6Al-4V alloy, the gas tungsten constricted arc welding (GTCAW) was established to be beneficial than the gas tungsten arc welding process. The performance of welded joints depends on the fusion zone grain size (FZG) and fusion zone hardness (FZH), which need to be suitably optimized and controlled to attain advantageous mechanical characteristics of the joint. Hence, in this research study, efforts were taken to develop empirical relationships for predicting the FZH and FZG incorporating very important GTCAW parameters. Parameter optimization was performed using response surface methodology. Additionally, the influence of GTCAW parameters on FZG and FZH was analyzed. From the results, it is inferred that the inter-pulse frequency has better influence on FZG and FZH compared to other parameters.