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Mechanical properties of thermally-stable, nanocrystalline bainitic steels

Published version
Peer-reviewed

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Authors

Hulme-Smith, CN 
Bhadeshia, HKDH 

Abstract

Two novel, thermally stable bulk nanocrystalline bainitic steels were subjected to a range of mechanical tests. One alloy, containing 0.72 wt% carbon exhibited an ambient-temperature 0.2% proof strength of 1500 MPa and a fracture toughness of 64.6 MPa m21 after the bainite transformation. The other, containing 0.45 wt% carbon and 13.2 wt% nickel, had a 0.2% proof stress of 1000 MPa and a fracture toughness of 103.8 MPa m21. Both steels showed excellent creep resistance, with a rupture life at 450 °C and 700 MPa of 114 h and 94.8 h, respectively. Both displayed fatigue lives consistent with other steels of similar structure in the literature. After thermal exposure at 480 °C for 8 d, both steels increased in strength to 1800 MPa, and 1600 MPa, respectively. The latter steel reduced in fracture toughness to 19.6 MPa m21. These alloys are suitable for a range of engineering applications and remain so after thermal exposure. Combined with impressive high-temperature performance, this makes the current alloys candidates for use in some elevated temperature applications.

Description

Keywords

Mechanical characterization, Nanostructured materials, Bainite

Journal Title

Materials Science and Engineering: A

Conference Name

Journal ISSN

0921-5093
1873-4936

Volume Title

700

Publisher

Elsevier BV
Sponsorship
Engineering and Physical Sciences Research Council (EP/H022309/1)
EPSRC (1306243)
Engineering and Physical Sciences Research Council (EP/M005607/1)
EPSRC RG64823, Rolls-Royce plc