Inoculation as grain refinement strategy for Wire Arc Manufacturing of Invar 36

Additive manufacturing (AM) refers to a series of techniques in which parts are created by successive deposition of layers. Among the different technologies, Wire Arc Additive Manufacturing (WAAM) employs a welding system in combination with a motion mechanism to deposit layers of molten metal. This technology possesses high deposition rates and...

Cleavage Fracture Micromechanisms of High Strength Steel and its Heat-Affected Zones

The use of materials in increasingly severe service conditions raises concerns about structural safety with respect to cleavage fracture. There are three main material-related challenges that structures face under harsh environments: 1) the trade-off between strength and toughness; 2) the ductile-to-brittle transition behaviour of BCC high...

Microstructure-based cleavage modelling to study grain size refinement and simulated heat affected zones of S690 high strength steel

Study of the cleavage behavior of heat treated S690 steel by a microstructure-based approach combined with finite element analysis is present in this paper. Cleavage simulations of steels subjected to heat treatments that cause grain refinement or simulate heat affected zones are performed, and are compared with experiments. It is found that...

Effect of isoparametric grain refinement on mechanical properties and cleavage fracture toughness in high strength steels

In recent decades, high strength steels in thick sections have been increasingly used in offshore structures where they are subjected to harsh service conditions such as freezing temperatures and high static/dynamic loading. At these conditions they are susceptible to a transition from ductile failure to a dangerous brittle (cleavage)...

Dislocation-induced breakthrough of strength and ductility trade-off in a non-equiatomic high-entropy alloy

In conventional metallic materials, strength and ductility are mutually exclusive, referred to as strength-ductility trade-off. Here, we demonstrate an approach to improve the strength and ductility simultaneously by introducing micro-banding and the accumulation of a high density of dislocations in single-phase high-entropy alloys (HEAs). We...

Cavitation-aided grain refinement in aluminium alloys

This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditions of the stable grain refinement effect in...

Hydrogen Storage in Nanostructured Light Metal Hydrides

The global energy issues can be solved by the abundantly available hydrogen on earth. Light metals are a compact and safe medium for storing hydrogen. This makes them attractive for vehicular use. Unfortunately, hydrogen uptake and release is slow in light metals at practical temperature and pressure conditions. Catalysts are known to accelerate...