Publications by Robin Schäublin

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The microstructure and tensile behavior of pure single crystalline Ni irradiated to low doses at room temperature with 590 MeV protons are investigated. Tensile tests performed at room temperature show radiation induced hardening, which increases with increasing dose. The microstructure of irradiation induced defects observed under transmission electron microscopy consists of about 50% stacking fault tetrahedra, 30-40% dislocation loops and 10% of unidentified features. In addition, the irradiated and defor

Ferritic/martensitic steels considered as first-wall candidate materials for fusion reactors experience significant radiation hardening at temperatures below similar to400 degreesC. Experimental evidence suggests that the observed defects are large interstitial dislocation loops with Burgers vector b = and b = (1)/(2). In this work, the atomic character of and (1)/(2) loops is investigated with molecular dynamics simulations and the atomic configurations are used to calculate the defec

The microstructural characterization of two titanium alloys, Ti5Al2.5Sn and Ti6Al4V, was performed. These alloys were selected as representatives of the alpha and alpha + beta titanium families, to investigate their possible application as structural materials in fusion reactor technology. Scanning and transmission electron microscopy have been used to obtain the relevant features of the microstructure in the as-received state and after mechanical deformation in tensile and fatigue experiments. Deformation

Implantation of Ni ions into pure aluminium shows the formation of amorphous zones (AZ). Measurements by energy dispersive spectrometry attribute to the amorphous zones at Ni concentration of 25 at.%. These amorphous regions are relatively stable under heating and persist after post-implantation treatment. To understand microscopically this stability, molecular dynamic simulations (MD) are done. Using embedded atom method potentials, an amorphous Al3Ni is first obtained. The melting temperature determined f

Irradiation-induced hardening and loss of ductility of ferritic/martensitic materials envisaged for future fusion reactor is still difficult to understand. In particular, helium (He), produced by transmutation by the fusion neutrons of 14 MeV, is known to ...

Radiation effects on the mechanical behavior and the microstructure of pure her, titanium polycrystals have been investigated. Results have been analyzed in the frame of a dispersed obstacle hardening model and compared to those previously obtained for pure metals with a fcc or bee structure. such as Cu and I'd or Fe. respectively. Differences in the defect accumulation rate and the dose dependence of hardening are discussed in terms of possible irradiation hardening mechanisms for the hcp structure. (C) 20

Molecular dynamics simulations were performed to estimate the dissociation energies of helium interstitials, vacancies and self-interstitial atoms from small helium-vacancy clusters. Several sets of empirical potentials have been tested and compared with a ...

Polycrystalline specimens of the ferritic-martensitic OPTIMAX A steel have been irradiated on the one hand with neutrons at 523 K to a dose of 2.5 dpa and with 590 MeV protons at ambient temperature and 523 K to doses of about 0.3 and 1 dpa on the other. Charpy tests reveal a shift of the ductile-to-brittle transition temperature from about 190 to 268 K in the neutron-irradiated steel. Proton irradiations at ambient temperature lead to hardening and reduction of tensile ductility of the material. Both pheno

Martensitic Ni-Ti was observed to transform to the austenitic phase due to defects introduced either by ion or electron irradiations at a temperature where the martensitic phase is normally stable. The phenomenon was studied by molecular dynamics simulatio ...

The microstructure of the F82H steel that is a candidate for the future fusion reactor first wall is investigated. Protons as well as fission neutrons are used to simulate the irradiation effects of the fusion environment. The differences in the He production rates between the two types of irradiation may lead to differences in the irradiation damage of the F82H microstructure. This paper presents a transmission electron microscopy (TEM) study for three different irradiation conditions: (i) in the PIREX fac

Irradiation induces the formation of stacking fault tetrahedra (SFTs) in a number of fcc metals, such as stainless steel and pure copper. In order to understand the role of the material's parameters on this formation, pure Cu, Ni, Pd and Al, having a respe ...

Crystal damage induced by irradiation is investigated using transmission electron microscopy (TEM) coupled to molecular dynamics (MD) calculations. The displacement cascades are simulated for energies ranging from 10 to 50 keV in Al, Ni and Cu and for times of up to a few tens of picoseconds. Samples are then used to perform simulations of the TEM images that one could observe experimentally. Diffraction contrast is simulated using a method based on the multislice technique. It appears that the cascade indu

The implantation of Ni ions into pure Al leads to the formation of similar to 10 nm amorphous zones (AZ) which induce diffuse rings in the diffraction pattern in addition to the diffraction spots of the crystal. Measurements by energy dispersive spectrometry and electron energy loss spectrometry attributed to the amorphous zones an average Ni concentration of 25 at%. The exact structure of these AZ is still unknown. The structure is characterized here by both the total and partial radial distribution functi

TEM image simulations are used to couple the results from molecular dynamics (MD) simulations to experimental TEM images. In particular we apply this methodology to the study of defects produced during irradiation. MD simulations have shown that irradiation of FCC metals results in a population of vacancies and interstitials forming clusters. The limitation of these simulations is the short time scales available, on the order of 100 s of picoseconds. Extrapolation of the results from these short times to th

Polycrystalline pure Fe and Fe-12Cr alloy have been proton-irradiated to doses of 10(-3)-3 x 10(-1) dpa at room temperature and 523 K. Samples were mechanically tested in tension and transmission electron microscopy (TEM) was performed on the as-irradiated material as well as on the irradiated and deformed material. At room temperature, pure Fe presents an initial yield point, that increases with the dose, followed by a yield region, indicative of a localized deformation mode. The Fe-12Cr alloy shows the sa

Molecular dynamics simulation is one of the most useful methods to model defect generation and subsequent change in mechanical properties in material that will suffer irradiation in the future fusion reactors. This work is aimed at showing the influence of ...

The effects of neutron irradiation on austenitic stainless steels, usually used for the manufacturing of internal elements of nuclear reactors (e.g. the core shrouds), are the alteration of the microstructure, and, as a consequence, of the mechanical prope ...

The microstructural modifications due to irradiation in hcp pure metals and their consequences on the mechanical properties have been investigated. Experimental results for proton-irradiated pure polycrystalline titanium are presented and discussed. Sample ...

A review of the microstructure of irradiated reduced activation ferritic/martensitic steels is presented, with a focus on F82H. Because of its resistance to irradiation induced hardening, swelling and low irradiation induced temperature shift in the ductile to brittle transition, this class of steels is a candidate structural material in future fusion reactors. The microstructure induced by irradiation is investigated in order to identify the key elements to deformation mechanisms. The study is focussed on

The microstructure and tensile behavior of pure single crystalline Ni irradiated with 590 MeV protons are investigated. First results have been obtained for a damage level of 0.13 dpa at room temperature and 0.002 dpa at 523 K. The irradiation induced defect microstructure observed under transmission electron microscopy consists of loops and stacking fault tetrahedra in a lower density. Tensile tests were performed at room temperature and show observable radiation induced hardening already at 0.002 dpa. Dis

Robin Schäublin

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Irradiation induced behavior of pure Ni single crystal irradiated with high energy protons

(100)-loop characterization in alpha-Fe: comparison between experiments and modeling

Microstructure of Ti5Al2.5Sn and Ti6Al4V deformed in tensile and fatigue tests

Stability of Al0.75Ni0.25 amorphous zones induced by Ni ion implantation into pure aluminium

Effect of helium on irradiation-induced hardening of iron: A simulation point of view

Structure-mechanics relationships in proton irradiated pure titanium

Stability of helium bubbles in alpha-iron: A molecular dynamics study

The mechanical properties and microstructure of the OPTIMAX series of low activation ferritic-martensitic steels

The effect of point defects on the martensitic phase transformation

Differences in the microstructure of the F82H ferritic/martensitic steel after proton and neutron irradiation

Irradiation-induced stacking fault tetrahedra in fcc metals

Correlation of simulated TEM images with irradiation induced damage

Structure analysis by diffraction of amorphous zones created by Ni ion implantation into pure Al

Correlating TEM images of damage in irradiated materials to molecular dynamics simulations

Tensile properties and microstructure of 590 MeV proton-irradiated pure Fe and a Fe-Cr alloy

Effect of interatomic potential on the behavior of dislocation-defect interaction simulation in α-Fe

Mechanical properties-micro structure correlation in neutron irradiated heat-affected zones of austenitic stainless steels

Temperature dependence of irradiation effects in pure titanium

Microstructure of irradiated ferritic/martensitic steels in relation to mechanical properties

The microstructure and tensile properties of pure Ni single crystal irradiated with high energy protons