The Properties Of The Vanadium Based Alloys Affected By Trace Alloying Elements Simulated Via The Theoretical Way

A combination of low induced radioactivity,good resistance to neutron radiation damage and good elevated-temperature strength makes vanadium-based alloys be very important structural materials in the nuclear industry.Because of its good properties,many works having been taken on these areas.In this paper,the distributions of the alloying atoms in the vanadium based alloys and their effects are studied on atomic level and microstructure through the methods of first principles and molecular dynamics.It is worth noting that the Ti-rich precipitates were observed in detail in this paper,and the influence of Ti-rich precipitates on the properties of vanadium based alloys was analyzed.It is implied that the Cr atoms can exist in any place of the vanadium-based alloys stably via our research by the methods of the first principles and molecular dynamics.The grain boundary of the vanadium-based alloys have been strengthened effectively when segregated Cr atoms also at the grain boundary.Differently,it is tend to be internal segregation for the grains because of the existence of the Ti atoms and a certain Ti-rich region is also formed at the same time.Because of these results,the elastic deformation of vanadium based alloys become weaker and its toughness become worse.In addition,the grains can be refined by adding the Y elements which leading to the dispersion strengthening,enhancing the mechanical property of the vanadium based alloys confirmed by our work via the first principles.Furthermore,the microstructures of Ti-rich precipitates have built according to the experimental results.Then,a series of basic parameters have calculated based the structure mentioned above.It is found that the Ti-rich precipitates are brittle phase and the hardness of Ti-rich precipitates are much higher than the pure V metal.The mechanical properties of the vanadium based alloys are greatly reduced due to the existence of the Ti-rich precipitates.The interfaces between the Ti-rich precipitates and matrix phase also have been studied.Comparing to the interfaces between the pure vanadium and interface between TiO and matrix phase,the strength of the latter has increased,but the adhesions among the atoms in TiO grain have decreased.For the Ti-rich precipitates Ti(CNO)under steady states,the cohesion of the interface between Ti(CNO)and matrix phase becomes weak when the impurity O atom on its interface.