Research On Laser Assisted Indentation Forming Of Three-sided Pyramid Nano Indenters

For a long time,special phenomena in real life,such as wall climbing by geckos and hydrophobic lotus leaves,have attracted people’s attention.With the development of science and technology,people have found that the reason for these special phenomena is that animals and plants have special structures on the surface.Inspired by this,researchers can process ordered micro and nano structures on the surface of materials to improve their surface properties.This research has gradually become one of the hot spots at home and abroad.There are many ways to process micro and nano structures,including micro machining,particle beam machining and lithography technology,etc.Micro machining can realize the micro structure of any shape,and the workpiece materials processed have a wide range of application.Particle beam machining can obtain micro and nano structures with high precision,low pollution and no oxidation.The lithography technology can be used to fabricate a wide range of micro and nano structures with high shape accuracy.However,in order to meet the requirements of smaller and smaller structure size and higher and higher accuracy of shape,this poses new challenges to micro and nano machining and manufacturing technology.Nano indentation technology has been widely concerned in processing and forming,this processing technology has a large processing range,does not produce chips and small tool wear,low cost and high production efficiency,is a good method of material surface processing micro/nano structure;At the same time,as a kind of auxiliary processing technology,laser assisted heating processing has developed rapidly in recent years.Laser with high energy density,accurate and rapid heating process and adjustable spot size is used as heat source for heating.In this paper,the combination of the two is used as a method for machining micro-nano structure,which can promote the development of micro-nano structure machining technology.The main research work carried out in this paper is as follows:In view of the research on micro-nano structure processing methods,the method of laser heating assisted motion stamping process of triangular pyramid nano indenter is proposed,and a set of processing device of thermal field assisted triangular pyramid nano indenter imprinting materials is built.The device is divided into two parts,one is the stamping device,the nanoindenter with triangular pyramid shape and diamond material is used as the cutting tool,and the actuator is piezoelectric positioning platform.With high precision electric translation table,mimicking nano indentation technology,can complete the relevant stamping work;The other part is the auxiliary heating device,using fiber output semiconductor laser as heat source;The combined experimental device was used to carry out machining experiments to study the feasibility of this machining method.The finite element model of aluminum alloy block material was established according to the heat conduction theory.The finite element software COMSOL was used to simulate laser heating of aluminum alloy surface,and the surface temperature field was studied to analyze the influence of different laser parameters on the distribution of the temperature field on the material surface.The finite element software ABAQUS was used to study the machining process of nano-indentation technology by finite element simulation method.The twodimensional and three-dimensional finite element models were established to simulate the indentation technology,and the influence of different temperature,different loading speed and different tool center Angle on the surface mechanical response was studied.The finite element simulation surface morphologies of single-point and two-point stamping were obtained.The accuracy of the finite element simulation model was verified by using the single point printing experiment.Nano-indenter was given different loading speed to observe the influence of indentation under different conditions.Two-and multi-point embossing experiments were carried out to explore the influence of embossing distance and other factors on the indentation morphology.The indentation morphology formed by conventional indentation and heated indentation was observed by laser heating assisted indentation system,and the surface forming accuracy was observed to obtain the process parameters for preparing the best indentation morphology.