| High performance components serve in harsh environment,and are the core components of superaircraft,launch vehicle,rail space station and nuclear fusion equipment,such as ultra high load bearing,extreme heat resistance,ultra light weight and high reliability.As its performance is influenced by the coupling of multiple factors,it poses a severe challenge to its material characteristics and manufacturing methods: the material needs to be lightweight and high-strength,and the integrated integral forming,which requires precise and controllable geometric dimensions,is made.Traditional high-performance materials are faced with technical bottlenecks,such as preparation and forming separation,long process and low flexibility.Therefore,it is urgent to seek an integrated preparation and forming method of high performance materials to ensure that the components have super high and controllable comprehensive mechanical properties and have complex overall structures.The technology of hot isostatic pressing is combined with the mould control technology under high temperature and high pressure,which can make the powder material quickly and completely shape the complex parts of the forging parts.At the same time,the controllable loading temperature and pressure can be used to realize the preparation and regulation of the material.The technology has been regarded as a potential manufacturing technology by developed countries such as the United States,Russia and the United Kingdom.FGH97 nickel base superalloy is a recently developed high-temperature nickel based alloy in China.It has been widely used in the manufacture of engine turbine discs.TA15 titanium alloy is a typical high temperature titanium alloy near alpha type.It has good thermal strength of the titanium alloy and also has good shaping properties of(alpha + beta)type titanium alloy.It is widely used in aircraft fuselage and engine manufacturing.In this paper,the hot isostatic pressing technology is used to form FGH97 nickel base superalloy and TA15 titanium alloy.Specific research work and results are as follows:In heat isostatic pressing nickel base superalloy,the problem of the particle boundary to gather carbide and reduce the mechanical properties of the workpiece is aimed at the heat isostatic pressing of nickel base superalloy,the particle boundary is concentrated to gather carbides and reduce the mechanical properties of the parts.This paper compares the new asynchronous loading process with temperature rising and pressurization,and the traditional synchronous loading process of simultaneous heating and boosting.It is found that,compared with the synchronous loading process,the grain size of the asynchronous loading process is 256.32 ?m,which is about 17 times(15.09 ?m)of the grain size of the synchronous loading process,but the mechanical properties of the asynchronous loading process are better than those of the synchronized loading process.It is speculated that the grain size of the synchronous loading process is small,but at the same time the original powder particle boundary is dense.The densification behavior,microstructure evolution and tensile properties of the TA15 titanium alloy are systematically studied under the representative thermal isostatic pressure(930 ?,980 ? and 1030 ?)under the current hot isostatic pressure forming of TA15 titanium alloy.The results show that the grain size increases with the increase of hot isostatic pressing temperature.At 930 ?,the microstructure of the work piece is double structure while the hot isostatic pressing temperature is over TA15.The alloy is mainly composed of Wechsler structure when the temperature of the phase transition point is(954 ?).The tensile strength of the 980 ? hot isostatic pressing parts decreased slightly compared with the other two groups,but the plasticity of the products increased significantly compared with the other two groups. |
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