Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

We have investigated the influence of deformation-induced defects on the isothermal precipitation at 550?°C in as-quenched (solute-supersaturated) and annealed (solute-depleted) Fe-Cu and Fe-Cu-B-N alloys by positron annihilation spectroscopy and hardness tests. Using the coincidence Doppler broadening technique, the evolution of local...

In situ determination of aging precipitation in deformed Fe-Cu and Fe-Cu-B-N alloys by time-resolved small-angle neutron scattering

We performed in situ time-resolved small-angle neutron scattering (SANS) measurements on high-purity Fe-Cu and Fe-Cu-B-N alloys during isothermal aging at 550 °C in order to study the potential self-healing of deformation-induced defects by nanosized Cu precipitation. Three different samples with 0%, 8%, and 24% prestrain were used to study the...

Self healing of creep damage in boron and copper containing iron alloys (abstract)

The generation of deformation damage during fatigue loading in Al-Cu alloy studied by the Doppler Broadening technique

We have investigated the evolution of damage during fatigue loading in Al–Cu 2024-T3 alloys using the positron annihilation Doppler Broadening (DB) technique. This technique enables us to monitor in a non destructive way, at the atomic and vacancy level, the formation of deformation defects and their interaction with solute atoms at selected...

Effect of carbon on copper precipitation in deformed Fe-based alloys studied by positron annihilation spectroscopy

The role of deformation-induced defects and carbon addition on the copper precipitation during aging at 550 oC is investigated in high-purity Fe-Cu-B-N-C alloy samples by Coincidence Doppler Broadening. In samples with 0% and 8% cold pre-strain, the influence of tensile pre-deformation on the precipitation kinetics of copper is studied. The...

Self healing by Cu precipitation in deformed Fe-Cu-B-N-C

Steels are among the most widely used construction materials as their mechanical properties can be tuned over a very wide range of desired combinations of strength formability and other properties. However, when exposed for long times to high temperatures steel components can exhibit premature and low-ductility creep fracture, which arises from...

Self healing by Cu precipitation in deformed Fe-Cu-B-N-C

Steels are among the most widely used construction materials as their mechanical properties can be tuned over a very wide range of desired combinations of strength formability and other properties. However, when exposed for long times to high temperatures steel components can exhibit premature and low-ductility creep fracture, which arises from...

Enhancing the creep life of steels by self-healing through dynamic in-service precipitation

Abstract only.

Position-dependent shear-induced austenite– martensite transformation in double-notched TRIP and dual-phase steel samples

While earlier studies on transformation-induced-plasticity (TRIP) steels focused on the determination of the austenite-to-martensite decomposition in uniform deformation or thermal fields, the current research focuses on the determination of the local retained austenite-to-martensite transformation behaviour in an inhomogeneous yet carefully...

High-resolution X-ray diffraction investigation on the evolution of the substructure of individual austenite grains in TRIP steels during tensile deformation

The martensitic transformation behaviour of the metastable austenite phase in low-alloyed transformation-induced plasticity (TRIP) steels has been studied in situ using high-energy X-ray diffraction during deformation. The austenite stability during tensile deformation has been evaluated at different length scales. A powder diffraction analysis...

Autonomous Repair Mechanism of Creep Damage in Fe-Au and Fe-Au-B-N Alloys

The autonomous repair mechanism of creep cavitation during high-temperature deformation has been investigated in Fe-Au and Fe-Au-B-N alloys. Combined electron-microscopy techniques and atom probe tomography reveal how the improved creep properties result from Au precipitation within the creep cavities, preferentially formed on grain boundaries...

Towards self-healing creep resistant steels

We report the main findings of our work on the behaviour of binary Fe-Cu and Fe-Au model alloys designed to explore routes to create new creep resistant steels having an in-built ability to autonomously fill creep induced porosity at grain boundaries. The alloying elements were selected on the basis of their ability to be brought in...