Predictive analytical modelling and experimental validation of processing maps in additive manufacturing of nitinol alloys

Nitinol (NiTi) shape memory alloys fabricated by Laser Powder Bed Fusion (L-PBF) Additive Manufacturing (AM) have attracted much attention in recent years, as compared with conventional manufacturing processes it allows to produce Nitinol parts with high design complexity. Avoidance of defects during L-PBF is crucial for the production of...

Controlling microstructure evolution and phase transformation behavior in additive manufacturing of nitinol shape memory alloys by tuning hatch distance

Laser powder bed fusion (L-PBF), categorized as additive manufacturing technique, has a capability to fabricate NiTi (Nitinol) shape memory alloys with tailorable functional properties and complex geometries. An important processing parameter, hatch distance (h), is often related to macroscale structural defects; however, its role on...

Superelastic response and damping behavior of additively manufactured Nitinol architectured materials

In energy absorption applications, architectured metallic materials generally suffer from unrecoverable deformation as a result of local yield damage or inelastic buckling. Nitinol (NiTi) offers recoverable deformation and energy dissipation due to its unique superelasticity, which can change the way we design and additively manufacture...

Achieving superelasticity in additively manufactured Ni-lean NiTi by crystallographic design

Superelastic metallic materials possessing large recoverable strains are widely used in automotive, aerospace and energy conversion industries. Superelastic materials working at high temperatures and with a wide temperature range are increasingly required for demanding applications. Until recently, high-temperature superelasticity has only...

Effects of boron addition on the high temperature oxidation of MoSi₂ alloys

Boron containing MoSi₂ is a promising material for applications at high temperature, but the oxidation mechanism is still unclear. In this work, the high temperature (1100 °C) oxidation of B doped MoSi₂ in synthetic air has been investigated. A (boro)silicate layer is formed on the surface of the alloy, which features a...

Effect of heat treatment on microstructure and functional properties of additively manufactured NiTi shape memory alloys

Additive manufacturing of NiTi shape memory alloys has attracted attention in recent years, due to design flexibility and feasibility to achieve four-dimensional (4D) function response. To obtain customized 4D functional responses in NiTi structures, tailorable phase transformation temperatures and stress windows as well as one-way or two-way...

Healing cracks in additively manufactured NiTi shape memory alloys

The pursuit of enhancing NiTi superelasticity through laser powder bed fusion (L-PBF) and [001] texture creation poses a challenge due to increased susceptibility to hot cracking in the resulting microstructure with columnar grains. This limitation restricts NiTi's application and contributes to material waste. To overcome this, we introduce...

Mo(Al_xSi_1−x)₂ healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium

To prevent premature triggering of the healing reaction in Mo-Si containing self-healing thermal barrier coating system, an oxygen impenetrable shell (α-Al₂O₃) around the sacrificial healing particles (MoSi₂) is desired. Here an encapsulation method is presented through selective oxidation of Al in Mo(Al<sub>x...