On The Development Of The Creativity Of Postgraduates

In recent years,the aerospace,marine ships,and deep-sea equipment industries have developed rapidly.This is mainly due to the development of new lightweight alloy materials.Among them,titanium(Ti)alloy materials have attracted great attention in the industry due to their excellent comprehensive mechanical properties,such as high strength,light weight,corrosion resistance,fatigue resistance,non-magnetic and high temperature resistance,etc.,in aerospace,Ocean exploration and engineering.Equipment,biomedical and many fields have been widely used.?-Ti alloy is such a kind of titanium alloy,favored by the industry.However,due to the high development cost,poor forgeability,and sensitive processing technology,the use of high-strength titanium alloys is greatly hindered.Therefore,it is very necessary to further develop low-cost,high-performance ?-Ti alloys and expand the application of Ti alloys.For ?-Ti alloys,improving its related defects by adding P-type stabilizing elements.We studied the effect of the addition of alloying elements on the related properties of Ti alloys,considering reducing costs and improving strength,we chose Fe element as the research object.Because it is not only a stable ?-type element,high strength and can easily form higher-strength alloys with other metals,but also cheap than some widely used alloy elements(V,Nb,Mo,etc.).This meets our low cost requirements.Based on the above basic requirements,using the first principles of basic methods,this article focuses on the following two parts:1.Effect of alloying element Fe on the phase transformation of ?-? in titanium alloys(1)Fe element can induce ?-? phase transformation of titanium alloy.Firstly,from the perspective of pure titanium phase transition,it can be concluded that the to of Ti is stable compared to ? phase,and after Fe is added,the phase transition of ? phase to ? phase of Ti can be realized.(2)The critical concentration of ?-? phase transition in titanium alloys induced by Fe.By the relevant theoretical derivation and NEB calculation method,we predict that the phase transition can be caused when the Fe concentration is about 6.7%.(3)Phase diagram relationship between Fe element and titanium alloy.A reasonable analysis of the E-V,H-P diagrams of Ti1-X-Fex alloys and the ?H-P diagrams of pure titanium yields a phase diagram relationship between Ti1-x-Fex alloys and pressure and Fe concentration.2.Effect of alloying element Fe on the mechanical properties of titanium alloy(1)The relationship between lattice constant and formation energy of Ti1-x-Fex alloy and Fe concentration.With the increase of Fe%,the lattice constant and the formation energy show a monotonic decreasing linear relationship.(2)The correlation between mechanical constants and Fe concentration shows a good curve relationship.With the increase of Fe%,the bulk modulus,shear modulus and Young's modulus of the alloy increase gradually,and the Poisson's ratio decreases.The stress-strain curve of the Tii_x-Fex alloy is calculated.The relationship between Fe%and tensile strength is obtained.As the Fe concentration increases,the tensile strength of the alloy increases gradually.(3)Theoretical calculation analysis.By calculating the electronic properties,the density of states map,electron localization function,and the charge density map between neighboring atoms are obtained.It is fully demonstrated that with the increase of Fe concentration,the interaction between atoms is enhanced,which results in the regularity of its mechanical properties.The root cause of the presentation.