Transformation mechanism of deformation-induced martensite in TiNbTaZr alloy

Ti-28Nb-15Ta-4Zr alloy with different rolling deformation was characterized by transmission electron microscopy.The results indicate that the alloy shows bcc β single phase before rolling,and deformation-induced α″ martensite is found during rolling deformation.The phase of α″ martensite is orthorhombic system and its lattice parameters are a=0.3152 nm,b=0.4854 nm,c=0.4642 nm.Misorientation relationship between β and α″ are α″//β,α″//β,α″//β,(100)α″//(100)β,(010)α″//(011)β,(001)α″//(01-1-)β.The crystal plane(01-1-)β being the habit plane transforms into(001)α″ during transformation from β to α″ phases,and martensite transformation mechanism is that the planes(100)β and(011)β transform to(010)α″ and(100)α″ through tiny migration of atoms.