Effect Of Heat Treatment Process On Microstructure And Properties Of Inconel X-750 Alloy

In this paper,InconelX-750 aloy was used as the research object.Thermo-Calc thermodynamic calculation,thermal simulation test,SEM,TEM,XRD,and phase analysis were used to systematicaly study the influence of aloying elements on the equilibrium precipitation phase,the influence of thermal deformation characteristics and heat treatment process on the microstructure and properties of the aloy,it will provide a scientific and theoretical basis for the application of Inconel X-750 aloy on large forgings.The specific research results are as follows:?1?The effect of aloying elements on the precipitation of the precipitated phase of Inconel X-750 aloy was investigated.It is found by simulation that the main equilibrium precipitates include??phase,MC phase and M₂₃C₆ phase in the al oy.The Ti element undergoes serious positive segregation duringnon-equilibrium solidification.With the increase of Al and Ti content,the maximum precipitation and maximum precipitation temperature of??increased,and the influence of Al element was more significant.With the increase of C content,the maximum precipitation of MC and M₂₃C₆ increased.As the Cr element increases,the maximum precipitation temperature of M₂₃C₆ increases.InconelX-750 aloy composition optimization results:C:0.03⁰.05%,Al:0.7⁰.9%,Ti:2².25%,Nb:0.75⁰.95%,Cr:13.5¹5.5%.?2?The thermal deformation behavior of InconelX-750 aloy under the deformation conditions of 0.1S^-1-10S^-1 and 950°C-1200°C was studied.The experiment found that the aloy can reach dynamic equilibrium during a strain rate of 0.1S^-1-1S^-1and at temperatures of 1100°C-1200°C.Under the other deformation conditions,the aloy exhibits continuous rheological softening during hot deformation.By establishing the thermal deformation constitutive equation of the aloy,the deformation activation energy of the aloy is calculated to be 377.12 KJ/mol.Based on the dynamic material model,the hot working diagram of the aloy is established.The hot working interval of the aloy is determined as follows:the deformation temperature is 1100°C-1200°C,and the strain rate is 0.1 S^-1-0.223S^-1.?3?The effect of heat treatment on the microstructure and properties of Inconel X-750 aloy was investigated.With the increase of solid solution time,the mechanical properties of the aloy are basically unchanged,and the grain size of the aloy increases slightly.After solution+water cooling and solution+oil cooling,there is no precipitation of??phase inside the aloy.After the aloy is aged,fine spherical??is precipitated,and fine block M₂₃C₆ and needle-shaped M₂₃C₆ are precipitated at the grain boundary.After aloy solution+air cooling,a small amount of fine spherical??precipitates in the aloy,and??is precipitated again after aging,and initial??slightly grows.After aloy solution+furnace cooling,large particle cubic??and small particle spherical??precipitated in the aloy,and large particle block M₂₃C₆ precipitated on the grain boundary.After the aloy is aged,the small spherical??is precipitated between the cubic??particles.There is no obvious change in initial??and grain boundary carbide.When the aging temperature increases,and the size of??phase increases,the aging temperature starts from 750°C,and the strength drops sharply.When the aging temperature is 720°C,the impact toughness reaches a minimum value..