Microstructure evolution and mechanical property response of TC11 titanium alloy under electroshock treatment

This work investigated the effects of electroshock treatment (EST) on the microstructure variation and mechanical properties of TC11 alloy. The average hardness of the specimens decreased from 358 HV to 328 HV after EST of 0.04 s, then increased to 396 HV after EST of 0.06 s. After EST, the yield strength of specimen declined from 959 MPa to 797 MPa after EST of 0.04 s, and then increased to 1265 MPa after EST of 0.06 s, but the fracture strain decreased continuously. The variation in mechanical properties was closely related to the phase transition from the secondary α (αs) to β phase, and the precipitation of refined needlelike α martensite (αM). The diffusion of atoms accompanied by broaden αs/β boundary from 11.2 nm to 27.6 nm due to the phase transformation after EST by 0.04 s and the dislocation pileup at the boundary to form defects, which resulted the decrease in strength. While increasing the EST time to 0.06 s, the width of αM/β boundary decreased to 5.91 nm. All results indicated that the EST is an effective method for optimizing the microstructure and mechanical properties of titanium alloys in a short time. [Display omitted] •Plenty of fine needlelike α martensite (αM) were precipitated after EST by 0.06 s.•The yield strength was increased from 959 MPa to 1265 MPa after EST by 0.06 s.•The average hardness was increased from 358 HV to 396 HV after EST by 0.06 s.•The fracture mode was transformed from plastic/brittle fracture to brittle fracture.•Above results caused by αM precipitates and the weave structures with dislocations.