The effects of silicon (Si) on the mechanical properties and fracture toughness of heavy-section ductile cast iron were investigated to develop material for spent-nuclear-fuel containers. Two castings with different Si contents of 1.78 wt.% and 2.74 wt.% were prepared. Four positions in the castings from the edge to the center, with different solidification cooling rates, were chosen for micros...

It is well known that when coarse-grained metals undergo severe plastic deformation to be transformed into nano-grained metals, their ductility is reduced. However, there are no ductile fracture criteria developed based on grain refinement. In this paper, we propose a new relationship between ductile fracture and grain refinement during deformation, considering factors besides void nucleation a...

Fracturing by ductile damage occurs quite naturally in metal forming processes, and ductile fracture of strain-softening alloy, here 42CrMo steel, cannot be evaluated through simple procedures such as tension testing. Under these circumstances, it is very significant and economical to find a way to evaluate the ductile fracture criteria (DFC) and identify the relationships between damage evolut...

The study of mechanical behavior of the structural steel S400 under quasi- static and dynamic loading has been the subject of this investigation. In oder to obtain different stress - triaxiality conditions the specimens were notched with 1, 1.5, 2 and 3.5 mm notch radius. The results of fractography show as the velocity of tension increases, ductility reduces and a ductile-brittle transition oc...

We introduce a lattice model able to describe damage and yielding in heterogeneous materials ranging from brittle to ductile ones. Ductile fracture surfaces, obtained when the system breaks once the strain is completely localized, are shown to correspond to minimum energy surfaces. The similarity of the resulting fracture paths to the limits of brittle fracture or minimum energy surfaces is qua...

Ductile fracture modeling still has to be improved at the macro and microscales. New numerical methods are applied to the limit analysis of cells containing one or several voids or void clusters. The results are compared with existing macroscopic models. Voids can also be introduced in analytical polycrystalline models, in order to combine plastic anisotropy and texture evolution with ductile f...

Mechanical degradation and resultant capacity fade in high-capacity electrode materials critically hinder their use in high-performance rechargeable batteries. Despite tremendous efforts devoted to the study of the electro-chemo-mechanical behaviours of high-capacity electrode materials, their fracture properties and mechanisms remain largely unknown. Here we report a nanomechanical study on th...

Precracked and notched specimens were used to investigate the fracture mechanism of a bainite steel at low temperature. The critical fracture event was studied using metallographic sectioning method. The results showed that the critical cleavage event was different in the precracked and the notched specimens. At -196C, all specimens fractured at lower-shelf region without any ductile crack grow...

The propensity of the transition of fracture type in either brittle or ductile cracked solid under mixed-mode I and III loading conditions is investigated. A fracture criterion based on the competition of the maximum normal stress and maximum shear stress is utilized. The prediction of the fracture type is determined by comparing smax=rmax at a critical distance from the crack tip to the materi...

In several practical cases, the ultimate ductile fracture strain determined with tensile test is accepted as a material plasticity measure 1 . In this case, the plasticity has to be defined as an ability of a material to accommodate high permanent strains until fracture appears where this strain reaches certain value called ultimate fracture strain p. The strain value until fracture depends not...