A First-principles Study On Phase Stability And Mechanical Properties Of Fe-Pd Shape Memory Alloy

Reasonable design of austenitic fcc phase Fe-Pd alloy has good shape memory properties and mechanical properties,and has important research value in both academic and application fields.It is expected to replace Ni-Mn-Ga alloy to become a better shape memory alloy material,which is one of the research hotspots in the field of materials.Along with the components,preparation process is different,each atom in the alloy holder will be different,which lead to the different degree of order of the atom,the alloy way of magnetic order may change,and eventually led to the martensite phase transformation structure change,fct has grown and bct phase of martensite phase,including from the fcc to fct has grown this process is reversible and thermal elastic transformation,can realize the shape memory effect of Fe-Pd alloy,but from the fcc to bct is irreversible,will not be able to realize the shape memory effect.Therefore,understanding the alloy composition and preparation process of alloy placeholder atoms and the influence of the magnetic and orderly,in order to understand these effects involution metallographic change regularity of stability and mechanical properties,reasonable and proper control of bct phase formation,effective use of easy to form the effective factors,fct has grown phase is the implementation of Fe-Pd alloy shape memory performance optimization of the key.For a large number of Fe-Pd shape memory alloys,it is difficult to measure one by one the alloy components and the atomic space occupying condition by experiment,and it is very difficult to calculate the atomic and its magnetic disorder problem as the first principle.At present,there is a lack of essential understanding on the influence of alloy composition and atomic occupation on martensitic phase transition and mechanical properties of Fe-Pd alloy.The first principle EMTO-CPA method is used to study Fe-Pd alloy.Due to the existing experimental data is less Fe-Pd alloy is not fully comparing calculation value and experimental value,we use Mn₂NiGa ordered alloy EMTO method opposite party phase to four phase martensite phase transformation,comparing the calculated value and experimental value to verify EMTO-CPA method for structural phase transformation calculation accuracy,and then studied the alloy composition and atomic placeholder for fcc phase,martensite phase austenite phase bct and fct has grown phase structure and phase stability,mechanical properties,thus looking for forming the favorable factors,fct has grown phase for excellent performance,explain the fcc phase further reasonable control of alloy composition,The optimization of shape memory performance of Fe-Pd alloy provides a theoretical basis.