Fabication of crack-free novel Ni-superalloy by additive manufacturing

Project description

Additive manufacturing (AM) through laser powder bed fusion (LPBF) processes are highly versatile that allows greater design freedom and near-net-shape fabrication, thereby leading to greater process efficiency and reduced material wastage. However, there exists significant challenges with the fabricability of high-performance materials, including Ni-based superalloys through additive manufacturing routes, especially LPBF. Specifically, the AM of Ni-based superalloys is often associated with stress-induced micro/macro cracking, pronounced texture and microstructural inhomogeneities. This is particularly true for high γ′ and γ′′-containing superalloys. CM247LC is one such class of Ni-superalloys that are known to be extremely prone to processing-induced cracks. Various mechanisms of cracking are associated with the deposition of high γ′ superalloys – this includes solidification, strain-age and liquation cracking, with strain-age and liquation cracking being the more difficult to control. In some cases, even when crack-free parts are manufactured through careful process parameter and microstructure control, post-deposition operations such as hot isostatic pressing and precipitation heat-treatments can still lead to renewed cracking, making the component unsuitable for operation. As a result of these issues, the creep strength of AM-LPBF CM247LC alloy is significantly poor as compared to its cast counterpart.
As the first part of this project, the printability of CM247LC will be improved by alloy modification, such that crack-free specimens can be additively manufactured. For the second part of this project, as a benchmarking for creep resistance, the high temperature properties of AM of modified-CM247LC would be compared against an AM-friendly novel superalloy composition of ABD900-AM. A test matrix would be constructed for comparison between the two Ni-superalloys.

Outcomes

1. To study the possibility of generating a crack-free Ni-superalloy CM247LC, that otherwise is extremely prone to processing-induced cracking through novel microstructural or process design. Then subsequently compare its high temperature properties with a novel AM superalloy.
2. One patent
3. 3-6 papers in international peer-reviewed journals.

Essential capabilities

Major in Metallurgical or Mechanical/Production Engineering, with 75% and above CGPA

Desireable capabilities

Some prior work experience in the field of manufacturing

Expected qualifications (Course/Degrees etc.)

Bachelors in Mechanical or Metalllurgical engineering; attended courses such as solidification, themodynamics and phase trasformation, welding etc