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Prediction of solidification cracking by an empirical-statistical analysis for laser cladding of Inconel 718 powder on a non-weldable substrate
摘要： This paper presents an empirical-statistical approach to predict solidification cracking during laser cladding of Inconel 718 powder on A-286 Fe-based superalloy. This approach is based on a linear regression analysis and empirical-statistical correlations between the key processing parameters (laser power, P; powder feed rate, F; and scanning speed, V) and the geometrical attributes of single laser cladding tracks. These correlations were used for the development of a processing map which assesses the effects of the geometrical characteristics on the solidification cracking and the required conditions to obtain crack-free clads. Scanning electron microscopy was used for microstructural characterization. Thermodynamic calculations using the non-equilibrium Scheil solidification model were also employed. The empirical-statistical analysis showed that the processing parameters directly associated with the height and angle of single laser cladding tracks are and, respectively. The processing map revealed that the dilution ratio is the governing macrostructural attribute required to avoid solidification cracking. Indeed, a substrate dilution ratio lower than 25% shifts the cladding composition to an alloy regime, which has lower susceptibility to solidification cracking. The role of this macrostructural feature in reducing the susceptibility of the fusion zone to solidification cracking is thoroughly discussed.
关键词： Thermodynamic simulation,Inconel 718,Processing map,Solidification cracking,Laser cladding,Dilution ratio
更新于2025-09-23 15:21:01
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A Simulation Study on Performance Improvement of Solar Assisted Heat Pump Hot Water System by Novel Controllable Crystallisation of Supercooled PCMs
摘要： Domestic hot water (DHW) has a significant share in building’s energy consumption. In order to reduce this consumption, various solutions have been proposed such as controlling the system in an efficient way, using renewable sources and using phase change materials (PCM) in the system to increase heat capacity. However, this study is not only offering heat capacity improvement of the DHW storage unit but also proposing that energy efficiency can be improved by controlling the heat releasing time of the PCM. In this study, supercooled PCM tubes are placed in a water tank and charged with a solar assisted heat pump unit, these supercooled PCM tubes can then be discharged anytime when the hot water is required. In this paper, a transient thermodynamic model is built for the whole system including solar collector, heat pump, water tank with PCM and DHW demand profile. System components are modelled and a 24 hours of demand profile is used in simulation for a UK home for summer and spring weather conditions. The results show that the PCM tubes effectively compensate the morning peak hot water demand and reduce daily energy consumption around 12.1% and 13.5% by shifting heating provision from immersion heater to solar heat pump.
关键词： Transient thermodynamic simulation,DHW,Supercooled PCM,Solar assisted heat pump
更新于2025-09-16 10:30:52
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Preparation of Tin Dioxide Nanoparticles by the Reverse Micelle Method: Experiment and Preliminary Calculations
摘要： Synthetic and computational experiments were carried out to study the influence of the nature and structure of surfactants, and also of the reaction medium on the size of tin dioxide nanoparticles obtained by the reverse micelle method.
关键词： tin dioxide,microemulsions,nanoparticles,molecular-thermodynamic simulation,synthesis in inverted micelles
更新于2025-09-09 09:28:46