Phase-Field Method Simulation Of Dendrite Growth Of Ti-Al Alloy

Ti-Al based alloy can be used at high temperature,and has the ad vantages of small density,oxidation resistance and f atigue resistance.The formation of dendrite greatly affects the properties of T i-Al alloy.The control of dend rite morphology is of great significance to improve the properties of the alloy.In the solidification process of dendrite,a lot of param eters and com plex boundary conditions are af fected,and the actual experiment is a high cost.Firstly this paper discusses the development of the phase field method and the related theory,the principle of entropy increase and the laws of thermodynamics based on introducing anisotropic structure,including the description of the temperature field and the concentration field and phase field order parameter equation,establish two element alloy phase field model.The num erical simulation program was used to simulate the dendrite growth of Ti-Al two a lloy by the established program model.This paper studied the influence of unifor m temperature field under the condition of anisotropic coef ficient,interfacial kinetics and interfacial morphology and the tip of the dendrite growth velocity,a preliminary study of t he non uniform temperature field conditions of dendrite growth.The conclusions are as follows:1)Effect of anisotropy on dendrite is m ainly reflected in the morphology and the growth rate of dendrite,the anisot ropy coefficient is sm all morphology of dendrite morphology was not obvious,when the anisotropy increases strength of dendrite will become more obvious br anches form,and produce two tim es the arm,and anisotropic strength the increase will accelerate the growth of dendrite.2)Influence of interface ener gy on the dendrit e is mainly reflected in the dendrite arm two times,when the interfacial energy is smaller dendrite morphology did not change significantly,with the increase of interfacial energy,dendrite growth speed,while two arm number.3)Effect of anisotropy coefficient on the de ndrite is also ref lected in the two arm,interfacial kinetics of the dendrite grow th rate incre ases with the in crease of running time increases,the dendrite af fected by the anisotropic strength coefficient is more significant.4)Under non isotherm al condition,the phase field with temperat ure gradient is more favorable for the growth of the tw o arm of dendrite than the isotherm al phase field.