TY - JOUR

T1 - Mechanical behavior and impact toughness of the ultrafine-grained Grade 5 Ti alloy processed by ECAP

AU - Semenova, I. P.

AU - Polyakov, A. V.

AU - Polyakova, V. V.

AU - Grishina, Yu F.

AU - Huang, Yi

AU - Valiev, R. Z.

AU - Langdon, T. G.

PY - 2017/6/1

Y1 - 2017/6/1

N2 - This paper reports on a study of the relationship between microstructure, mechanical behavior and impact toughness of the UFG Grade 5 Ti alloy. The mechanical behavior and impact toughness of the Grade 5 Ti alloy in a coarse-grained state, and in an ultrafine-grained (UFG) state produced by equal-channel angular pressing (ECAP) with subsequent deformation-and-thermal treatments via extrusion and warm upsetting in isothermal conditions, were studied extensively. It is shown that a strong refinement of α-grains (less than 250 nm) in the alloy by ECAP and extrusion leads to high strength but with low values of the uniform elongation and lower impact toughness. It is demonstrated that, in order to increase the impact toughness of UFG Ti alloys, it is possible to use approaches realizing ductility enhancement associated with an increase of the strain hardening capacity. An enhancement in the impact toughness of the UFG alloy through an increase in the uniform tensile elongation of the sample is achieved by the preservation of the ultrafine size of α-grains (about 800 nm) with predominantly high-angle boundaries and a decrease in the dislocation density due to recovery and dynamic recrystallization during warm upsetting.

AB - This paper reports on a study of the relationship between microstructure, mechanical behavior and impact toughness of the UFG Grade 5 Ti alloy. The mechanical behavior and impact toughness of the Grade 5 Ti alloy in a coarse-grained state, and in an ultrafine-grained (UFG) state produced by equal-channel angular pressing (ECAP) with subsequent deformation-and-thermal treatments via extrusion and warm upsetting in isothermal conditions, were studied extensively. It is shown that a strong refinement of α-grains (less than 250 nm) in the alloy by ECAP and extrusion leads to high strength but with low values of the uniform elongation and lower impact toughness. It is demonstrated that, in order to increase the impact toughness of UFG Ti alloys, it is possible to use approaches realizing ductility enhancement associated with an increase of the strain hardening capacity. An enhancement in the impact toughness of the UFG alloy through an increase in the uniform tensile elongation of the sample is achieved by the preservation of the ultrafine size of α-grains (about 800 nm) with predominantly high-angle boundaries and a decrease in the dislocation density due to recovery and dynamic recrystallization during warm upsetting.

KW - Ductility

KW - Impact toughness

KW - Strength

KW - Titanium alloy

KW - Ultrafine-grained structure

KW - Uniform elongation

UR - http://www.scopus.com/inward/record.url?scp=85018492784&partnerID=8YFLogxK

U2 - 10.1016/j.msea.2017.04.073

DO - 10.1016/j.msea.2017.04.073

M3 - Article

AN - SCOPUS:85018492784

VL - 696

SP - 166

EP - 173

JO - Materials Science and Engineering: A

JF - Materials Science and Engineering: A

SN - 0921-5093

ER -