Influence of β phase fraction on deformation of grains in and around shear bands in machining of titanium alloys

In machining of titanium alloys, β phase fraction influences their temperature stability and consequently the material deformation in and around shear bands in chips. To understand the influence, chips and chip roots generated during orthogonal machining of these titanium alloys with increasing β phase fraction viz. α, α+β, β rich α+β alloys were collected. Analysis of shear band characteristics and micro-mechanism of deformation of the material during machining shows that an increase in β phase fraction limits the spread of material deformation around the shear bands, reduces the spacing between them and prevents recovery micro-mechanism. Larger depth of machining affected zone in case of α and α+β alloy as compared to β rich alloy is attributed to their coarse grain size.