To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experimen...To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experiments were conducted under both dynamic and static loading conditions,allowing us to gather the micro-mechanical parameters of coal for further analysis of its micro-mechanical heterogeneity using the box counting statistical method and the Weibull model.The research findings indicate that the load–displacement curves of the coal mass under the two different loading modes exhibit noticeable discreteness.This can be attributed to the stress concentration phenomenon caused by variations in the mechanical properties of the micro-units during the loading process of the coal mass.Consequently,there are significant fluctuations in the micro-mechanical parameters of the coal mass.Moreover,the mechanical heterogeneity of the coal at the nanoscale was confirmed based on the calculation results of the standard deviation coefficient and Weibull modulus of the coal body’s micromechanical parameters.These results reveal the influence of microstructural defects and minerals on the uniformity of the stress field distribution within the loaded coal body,as well as on the ductility characteristics of the micro-defect structure.Furthermore,there is a pronounced heterogeneity in the micromechanical parameters.Furthermore,we have established a relationship between the macro and micro elastic modulus of coal by applying the Mori-Tanaka homogenization method.This relationship holds great significance for revealing the micro-mechanical failure mechanism of coal.展开更多
Stainless steel(SS)grade 316L is used for orthopedic implants due to its biocompatibility;yet the effort should be done to minimize the carcinogenic and inflammatory effects related to SS 316L implants.In this researc...Stainless steel(SS)grade 316L is used for orthopedic implants due to its biocompatibility;yet the effort should be done to minimize the carcinogenic and inflammatory effects related to SS 316L implants.In this research,aluminide coating of Al–Si alloy on SS 316L is characterized by using optical microscopy,energy dispersive spectroscopy(EDS),nano-indentation and corrosion testing technique.Hot dip aluminizing process is used to coat the SS 316L specimens at 765°C for 2 min immersion time.Half of the specimens are also diffusion treated in a Muffle furnace at 550°C for 4 h to produce diffused specimens of SS 316L.Microstructural examination shows the formation of flat coating/substrate interface due to Si addition.EDS analysis confirms the formation of complex intermetallic at the coating/substrate interface which finally results in increasing the hardness and corrosion resistance properties of coating.展开更多
基金Projects(U23B2093,52274245)supported by the National Natural Science Foundation of ChinaProject(KFJJ22-15M)supported by the Opening Project of State Key Laboratory of Explosion Science and Technology,China。
文摘To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experiments were conducted under both dynamic and static loading conditions,allowing us to gather the micro-mechanical parameters of coal for further analysis of its micro-mechanical heterogeneity using the box counting statistical method and the Weibull model.The research findings indicate that the load–displacement curves of the coal mass under the two different loading modes exhibit noticeable discreteness.This can be attributed to the stress concentration phenomenon caused by variations in the mechanical properties of the micro-units during the loading process of the coal mass.Consequently,there are significant fluctuations in the micro-mechanical parameters of the coal mass.Moreover,the mechanical heterogeneity of the coal at the nanoscale was confirmed based on the calculation results of the standard deviation coefficient and Weibull modulus of the coal body’s micromechanical parameters.These results reveal the influence of microstructural defects and minerals on the uniformity of the stress field distribution within the loaded coal body,as well as on the ductility characteristics of the micro-defect structure.Furthermore,there is a pronounced heterogeneity in the micromechanical parameters.Furthermore,we have established a relationship between the macro and micro elastic modulus of coal by applying the Mori-Tanaka homogenization method.This relationship holds great significance for revealing the micro-mechanical failure mechanism of coal.
基金sponsored and funded by Metallurgy and Materials Engineering Department,College of Engineering and Emerging Technologies, University of the Punjab (grant no.PU/ASR&TD/ RG-348 dated 26-1-2012)
文摘Stainless steel(SS)grade 316L is used for orthopedic implants due to its biocompatibility;yet the effort should be done to minimize the carcinogenic and inflammatory effects related to SS 316L implants.In this research,aluminide coating of Al–Si alloy on SS 316L is characterized by using optical microscopy,energy dispersive spectroscopy(EDS),nano-indentation and corrosion testing technique.Hot dip aluminizing process is used to coat the SS 316L specimens at 765°C for 2 min immersion time.Half of the specimens are also diffusion treated in a Muffle furnace at 550°C for 4 h to produce diffused specimens of SS 316L.Microstructural examination shows the formation of flat coating/substrate interface due to Si addition.EDS analysis confirms the formation of complex intermetallic at the coating/substrate interface which finally results in increasing the hardness and corrosion resistance properties of coating.
