Dynamic Strain Ageing of P91 Grade Steels of Varied Silicon Content

Authors

Ajit K. Roy, University of Nevada, Las VegasFollow
Pankaj Kumar, University of Nevada, Las VegasFollow
D. Maitra, University of Nevada, Las VegasFollow
Debajyoti Maitra, University of Nevada, Las VegasFollow

Document Type

Article

Publication Date

1-2009

Publication Title

Materials Science and Engineering A

Volume

499

Issue

1-2

First page number:

379

Last page number:

386

Abstract

Plate materials of modified 9Cr–1Mo steel (P91) containing four levels of silicon (Si) exhibited dynamic strain ageing (DSA) phenomenon characterized by gradually reduced failure strain and serrations in the engineering stress–strain diagrams under tensile loading within a temperature range of ambient to 400 °C. Since parameters including dislocation density (ρ), activation energy (Q) and work-hardening index (n) can play important roles in developing a mechanistic understanding of DSA, efforts have been made to evaluate them. A maximum value of ρ was calculated at 400 °C due to the formation of critical sized precipitates near grain boundaries, thus impairing the dislocation motion. The average value of Q ranged between 64 and 80 kJ/mole depending on Si content. The magnitude of n was gradually enhanced with increasing temperature up to 400 °C, followed by significant drop at 550 °C. Except for the alloy with 2.0 wt.% Si, the other tested materials exhibited a combination of intergranular cracking and cleavage failures at the primary fracture surface.

Keywords

Dislocation density; Dynamic strain ageing; Fractography; P91 grade steels; Silicon steel – Fatigue; Silicon steel – Fracture; Strain hardening; Strains and stresses; Surface hardening; Work-hardening index

Disciplines

Materials Science and Engineering | Mechanical Engineering | Mechanics of Materials | Metallurgy

Language

English

Permissions

Use Find in Your Library, contact the author, or interlibrary loan to garner a copy of the item. Publisher policy does not allow archiving the final published version. If a post-print (author's peer-reviewed manuscript) is allowed and available, or publisher policy changes, the item will be deposited.

Repository Citation

Roy, A. K., Kumar, P., Maitra, D., Maitra, D. (2009). Dynamic Strain Ageing of P91 Grade Steels of Varied Silicon Content. Materials Science and Engineering A, 499(1-2), 379-386.