Cracking behaviour and its suppression mechanisms with TiB2 additions in the laser additive manufacturing of solid-solution-strengthened Ni-based alloys

Zhang, Zhenhua, Han, Quanquan, Liu, Zhongyi, Wang, Liqiao, Zhang, Han, Zhao, Peng, Zhu, Guoliang, Huang, Chuanzhen and Setchi, Rossitza ORCID: https://orcid.org/0000-0002-7207-6544 2023. Cracking behaviour and its suppression mechanisms with TiB2 additions in the laser additive manufacturing of solid-solution-strengthened Ni-based alloys. Composites Part B: Engineering 266 10.1016/j.compositesb.2023.111023

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Abstract

This study systematically investigated the cracking mechanisms in the laser powder bed fusion (LPBF) of GH3230 solid-solution-strengthened Ni-based alloy (GH0). The results show that the micro-cracks that formed in GH0 specimens included both solidification and solid-state cracks. The initiation of solidification cracks was associated with the formation of continuous liquid films on high-angle grain boundaries at the final stage of solidification, while the solid-state cracks were found to be ductility-dip cracks, associated with a reduction in the material's plasticity within the heat-affected zone. The study also found that the residual stresses decreased with increasing LSS values, leading to reductions in crack length. The introduction of 1 wt% TiB2 particles to GH3230 (GH1-composite) was found to suppress cracking by promoting grain refinement and generating special high-angle grain boundaries, although residual thermal stresses increased. The ultimate tensile strength values of the GH0 and GH1-composite specimens at 900 °C were found to be 213 and 352 MPa, respectively. These findings provide significant insights into the LPBF of high-performance crack-free Ni-based superalloys.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	Elsevier
ISSN:	1359-8368
Date of First Compliant Deposit:	28 September 2023
Date of Acceptance:	24 September 2023
Last Modified:	08 Nov 2024 01:30
URI:	https://orca.cardiff.ac.uk/id/eprint/162810

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