Mechanical Properties Of Nickel-base Alloy Coating With Nano-Twin Structure

As the development trend of high-speed and light-duty internal combustion engines continues to advance,the piston rings,which are one of the core components,also tend to be light and thin.The thinning of the piston rings has certain improvements in the economy and operating stability of the internal combustion engine,but it also faces complex working conditions,poor working conditions,and can easily cause wear problems.For light and thin piston rings,the wear problem is even more serious.In order to solve this problem,there have been some surface treatment technologies for piston rings,such as hard chrome plating,surface nitriding,surface phosphating,spray coating,and vapor deposition.These technologies can increase the wear resistance of piston rings to a certain degree,and they can be extended its life,but these treatment processes are still not perfect,there are some drawbacks,such as the coating and the substrate is not enough bonding strength,high temperature stability is not good enough.The nickel-base alloy coating with nano twin structure studied in this paper has strong hardness and good thermal stability,and is suitable for being applied to the surface of a piston ring as an abrasion-resistant coating.To reduce wear and extend the life of the piston ring.In this study,molecular dynamics(MD)simulations were used to study the influencing factors of the hardness and elastic modulus of nickel-based alloys with nano twin structure.By using the control variable method,the twin layer thickness and temperature were analyzed in turn.The influence of the proportion of alloying elements on the hardness of the model.Through the analysis of the simulation data results,it is found that the thickness of the twin layer has a great influence on the mechanical properties of the nano twin structure nickel-base alloy coating: the nano twin structure can increase the hardness by 5.72 times and the elastic modulus by 7.9124 times.There is a critical twin layer thickness,when the twin layer thickness of the model is greater than at this critical thickness,its mechanical properties increase with the decrease of the thickness of the twin layer;conversely,when the thickness of the twin layer of the model is less than this critical thickness,its mechanical properties decrease as the thickness of the twin layer decreases.small.The critical thickness has a certain reference value for the production of nano twin structure nickel-base alloys and can play a role in guiding production.The composition of alloying elements also has a great influence on the mechanical properties of nanostructured nickel-base alloys.In this paper,a total of the five most common nickel-based alloying element ratios on the market have been selected,followed by nanoindentation simulations.The effect of alloying elements on the mechanics of the model was found.Finally,the effect of temperature on the mechanical properties of Ni-based alloys with nano twin structure was studied.Different nanoindentation temperatures were set up.The temperature distribution was from 300 K to 600 K and 50 K was used as an interval.The effect of temperature on the mechanical properties of the model is summarized by the indentation-load curve of the simulated nanometer indentation at different temperatures.In the subsequent study of the deformation mechanism,the deformation of the nano twin structure in the nickel-base alloy during the indentation process was analyzed,and the deformation law was analyzed to find out the origin and essence of the twin structure affecting the hardness.Through the extraction and analysis of the dislocation trends in each group during the nanoindentation process,dislocations are formed during the process of nucleation and propagation,and plugs occur near the twin boundaries.It can be seen that the twin boundaries have obvious obstacles to the dislocation lines,and the special role played by the twin boundaries in the development of dislocations is analyzed.Finally,this paper explores the influence mechanism of the thickness of different twin layers on the mechanical properties of the nano twin structure nickel-base alloy model.