Enhancing the mechanical properties of Ti-6554 alloys through an innovative strategy of magnetic field treatment before aging

Titanium alloys inevitably experience a reduction in ductility as strength improves. This study focuses on enhancing the strength of the Ti-6554 metastable beta titanium alloy through an innovative strategy involving magnetic field treatment before aging, while preserving its high ductility. Magnetic field treatment provides energy, accelerates dislocation motion, and increases the density of geometrically necessary dislocations. Meanwhile, the magnetic field can promote the transformation of beta phase to alpha phase and increase the volume fraction of alpha phase from 6.1 % to 8.4 %. The dislocations generated by the magnetic field serve as energy sources and precipitation sites for the subsequent aging precipitation of alpha phase, increasing the volume fraction of alpha phase to 11.1 %. As the alpha phase content increases, the alpha/beta phase interface also increases. Dislocations accumulate at the phase interface, hindering dislocation movement and contributing to the strengthening of the alloy at the phase interface. The samples treated with a magnetic field before aging exhibited higher strength and ductility than those treated with the conventional solution and aging process under the same parameters. Moreover, the magnetic field treatment increased elongation by similar to 32 %, resulting in the alloy exhibiting a magnetoplastic effect. Strength is improved by lattice friction stress, grain boundary strengthening, dislocation strengthening, and interface strengthening. Ductility is guaranteed by coordinated deformation through the primary alpha phase, alpha/beta interface, and activated pyramidal <c+a> slip.