TY - JOUR

T1 - Superplasticity and High Strength in Al–Zn–Mg–Zr Alloy with Ultrafine Grains

AU - Valiev, Ruslan Z.

AU - Kazykhanov, Vil U.

AU - Mavlyutov, Aydar M.

AU - Yudakhina, Anna A.

AU - Chinh, Nguyen Q.

AU - Murashkin, Maxim Yu

PY - 2019/8/21

Y1 - 2019/8/21

N2 - Herein, the ultrafine-grained (UFG) 7xxx series alloy Al–4.8Zn–1.2Mg–0.14Zr demonstrates superplasticity at unusually low temperatures of 120–170 °C while maintaining its high-strength state. The UFG structure is formed by high pressure torsion (HPT) at room temperature (RT), which leads to a considerable increase in the strength characteristics by ≈60% compared with the material after conventional heat treatment T6. It is found that the UFG alloy exhibits thermostability when testing or annealing up to 170 °C. Deforming by tensile test at a strain rate of 10−4 s−1 and 10−3 s−1, the elongation to failure at 120 and 170 °C exceeds 250% and 500%, respectively, whereas the strain rate sensitivity reaches 0.45, which is a typical value characterizing superplastic deformation. After superplastic deformation, the UFG alloy maintains 25–50% higher strength characteristics at RT than that after conventional heat treatment T6. The origin of such superior behavior of the UFG alloy is discussed.

AB - Herein, the ultrafine-grained (UFG) 7xxx series alloy Al–4.8Zn–1.2Mg–0.14Zr demonstrates superplasticity at unusually low temperatures of 120–170 °C while maintaining its high-strength state. The UFG structure is formed by high pressure torsion (HPT) at room temperature (RT), which leads to a considerable increase in the strength characteristics by ≈60% compared with the material after conventional heat treatment T6. It is found that the UFG alloy exhibits thermostability when testing or annealing up to 170 °C. Deforming by tensile test at a strain rate of 10−4 s−1 and 10−3 s−1, the elongation to failure at 120 and 170 °C exceeds 250% and 500%, respectively, whereas the strain rate sensitivity reaches 0.45, which is a typical value characterizing superplastic deformation. After superplastic deformation, the UFG alloy maintains 25–50% higher strength characteristics at RT than that after conventional heat treatment T6. The origin of such superior behavior of the UFG alloy is discussed.

KW - Al alloys,

KW - high strength,

KW - severe plastic deformation,

KW - superplasticity,

KW - ultrafine structures

KW - Al alloys

KW - high strength

KW - severe plastic deformation

KW - superplasticity

KW - ultrafine structures

KW - ELECTRICAL-CONDUCTIVITY

KW - ALUMINUM-ALLOYS

KW - MECHANICAL-PROPERTIES

KW - REFINEMENT

KW - PRECIPITATION

KW - SEVERE PLASTIC-DEFORMATION

KW - LOW-TEMPERATURE SUPERPLASTICITY

KW - DUCTILITY

KW - ROOM

KW - MICROSTRUCTURE

UR - http://www.scopus.com/inward/record.url?scp=85070913884&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/superplasticity-high-strength-alznmgzr-alloy-ultrafine-grains

U2 - 10.1002/adem.201900555

DO - 10.1002/adem.201900555

M3 - Article

AN - SCOPUS:85070913884

JO - Advanced Engineering Materials

JF - Advanced Engineering Materials

SN - 1438-1656

M1 - 1900555

ER -