The relationship between strain-age cracking and the evolution of γ′ in laser powder-bed-fusion processed Ni-Based superalloys

DOI: 10.1007/978-3-031-63937-1_77

Authors: J. F. S. Markanday (University of Cambridge) , N. D’souza (Rolls-Royce Plc) , N. L. Church (University of Cambridge) , J. R. Miller (University of Cambridge) , J. J. C. Pitchforth (University of Cambridge) , L. D. Connor (Diamond Light Source) , S. Michalik (Diamond Light Source) , B. Roebuck (National Physical Laboratory (UK)) , N. G. Jones (University of Cambridge) , K. A. Christofidou (University of Sheffield) , H. J. Stone (University of Cambridge)
Co-authored by industrial partner: Yes

Type: Conference Paper
Conference: Superalloys 2024
Peer Reviewed: No

State: Published (Approved)
Published: August 2024
Diamond Proposal Number(s): 33375

Abstract: Factors affecting strain-age cracking (SAC) have been quantitatively assessed in a range of Ni-base superalloys with differing γ′ contents. Differences in the amount of γ′ present in the as-built condition of HA282, STAL 15DE, CM247LC, and IN713LC are highlighted. In the as-built condition, γ′ are absent in HA282, but appear as nano-clusters in IN713LC. On heating, γ′ precipitates coherently in the γ phase, increasing the yield strength. The kinetics of precipitation are dependent on the heating rate and precipitation terminates at different temperatures in different alloys. The propensity to SAC is assessed via volume changes accompanying precipitation, increase in elastic modulus accompanying γ′ precipitation, and a loss in ductility/grain boundary cohesive strength with increasing temperature. A marked feature of additively built microstructures is the dramatically low grain boundary cohesive strength at ~800 °C, which is related to the segregation within the terminal liquid film at the grain boundary. The most important factor contributing to SAC is the lack of ductility and reduced grain boundary cohesive strength.

Diamond Keywords: Alloys

Subject Areas: Materials, Engineering


Instruments: I12-JEEP: Joint Engineering, Environmental and Processing

Added On: 25/08/2024 09:39

Discipline Tags:

Materials Engineering & Processes Materials Science Engineering & Technology Metallurgy

Technical Tags:

Imaging Tomography