The formation of a high-strength state in martensitic Ti Grade 4 by ECAP

This work is aimed at studying the features of initial Ti Grade 4 structure that affects the changes in its structure and properties during equal channel angular pressing (ECAP). A hot-rolled and martensite structure state, obtained in the process of water quenching from 950 degrees C were used as initial states. It has been established that ECAP of titanium in an initial martensitic state leads to the formation of a finer and more homogeneous structure than ECAP of a hot-rolled state. The share of high-angle boundaries reaches 80%, and the average size of structural fragments is 220 +/- 80 nm. After ECAP at 400 degrees C, recrystallized grains are observed. As a result, the ECAP of titanium in the initial martensitic state leads to more significant hardening of up to 1100 +/- 20 MPa compared to the hot-rolled state of -950 +/- 15 MPa. This will make it possible to reduce the number of technological operations, as well as improve the strength resource for heat treatment aimed at ductility enhancement in ultrafine-grained titanium.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study aims to investigate the features of the initial Ti Grade 4 structure and their effects on the structure and properties changes during equal channel angular pressing (ECAP). The results show that ECAP of titanium in an initial martensitic state leads to the formation of a finer and more homogeneous structure, resulting in more significant hardening compared to the hot-rolled state.