Study On Machining Distortion Law And Its Microscopic Mechanism Of Monolithic Component Of Titanium Alloy

The distortion of aerospace monolithic component is one of the striking problemsthat the aviation manufacturing has to face up to. Now titanium alloys are used widelyin aerospace monolithic components owing to theirs excellent comprehensivemechanical properties, low density, excellent corrosion resistance, outstanding high-heatstrength, creep strength and high-temperature stability. The research of materials scienceshows that the macroscopic properties of any substance depend on its microstructure.Currently, though significant researches concerning the distortion of aerospacemonolithic components have been conducted by many scholars, at home or abroad,these researches mainly included two aspects, the influence of residual stress on thedistortion and the finite element numerical simulation prediction, few researches takesmicrostructure into consideration. And these researches concerning the distortionmechanism of monolithic components are incomplete. A method combining experimentwith theoretical analysis is adopted. Then, the machining distortion law and itsmicrocosmic mechanism of monolithic component of titanium alloy are researcheddeeply and widely.Firstly, monolithic components of titanium alloy are designed by scaling based onthe real shape and dimension of beam parts, and the cutting parameters, processingmethod and clamping are same in the milling process. Then, the distortion of monolithiccomponents of titanium alloy is measured using three-coordinate measuring machine bystages, the distortion law of monolithic components of titanium alloy is obtained. Theresults of the experiment are the base of sampling of TEM and further study towards themicrocosmic mechanism of the distortion of monolithic component of titanium alloy.Then, the microstructure of monolithic component of titanium alloy of differentdistortion stages are observed and analyzed using TEM, the microstructure of differentdistortion stages is studied. And then the microstructure of the adjacent stages areanalyzed, the microstructure evolution of monolithic component of titanium alloy in theprocess of distortion is studied. Combined with the distortion law, the mechanisms ofthe distortion of monolithic component of titanium alloy finally are revealed. Finally, based on the above research, the mathematical relation model betweendislocation and the machining distortion of monolithic component of titanium alloy isestablished combining the dislocation dynamics with the theoretical calculation betweendislocation and the plastic deformation. The establishment of the model is a preliminarytheoretical exploration of the relationship between the microstructure evolution and thecorresponding plastic deformation, and it also provide an enlightening insight to revealthe mechanism of the distortion of monolithic component of titanium alloy.