Advanced micromechanical characterization and hydrogen embrittlement. Development of applications for the quality control and improvement of critical industrial components.
In this R&D Action Plan, funded by IDEPA and co-financed by the European Union, we are developing and validating new methodologies for the micromechanical characterization of structural steels and welded joints. The technology that we are developing is especially interesting in the case of welded joints, where the thermal cycles, to which both base metal and weld material are subjected, give rise to metallurgical changes and the appearance of different heat-affected sub-zones (fine-grained HAZ, Coarse-grained HAZ, inter-critical zone, etc.). All these zones have a different mechanical behavior. Due to the size of the test specimens, conventional mechanical tests are not able to characterize the behavior of the different subzones of the HAZ. Therefore, the quality control of these critical areas cannot be performed in detail, unless a sufficiently precise technology is developed to characterize these zones by means of miniature tests.
Hydrogen embrittlement is a complex phenomenon of degradation of the mechanical properties of steels and metal alloys. This hydrogen, very dangerous in pressure equipment, can be introduced during service (hydrocarbons, external agents, etc.) or during the manufacturing process, since processes such as welding or electrolytic coating generate a high risk of hydrogen diffusion in metals. In the case of equipment that will be exposed to hydrocarbons or aggressive external agents (petrochemical, offshore, energy, shipbuilding, etc.), it is of great interest to obtain the mechanical properties in a hydrogen environment to quantify the effect of hydrogen embrittlement on steels used in the manufacture. Conventional test techniques in hydrogen environments are complex and require a large amount of material for the machining of the specimens, so it is very interesting to develop miniaturized analysis techniques.
Finally, non-destructive testing (NDT) techniques allow the evaluation of the presence and size of defects in mechanically welded structures. However, there is no technique at present that allows to evaluate the mechanical properties in a non-destructive way. It is therefore of huge interest to develop a technique that allows, using very small portions of material, to evaluate the level of degradation of structural components.
Our development would imply a revolution in inspections of capital goods, shipbuilding structures, energy industry, aeronautics, etc., and a major improvement in the control and assurance of the structural integrity of critical components, where the breakage have major economic consequences and in the worst cases catastrophic effects.
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Our Selected Articles
T.E. García, C. Rodríguez, F.J. Belzunce, I. Peñuelas, B. Arroyo. Development of a methodology to study the hydrogen embrittlement of steels by means of the small punch test. Material Science & Engineering A- Struct, 626, 342-351, 2015.
S.P. Jeffs, R.J. Lancaster, T.E. García. Creep lifing methodologies applied to a single crystal superalloy by use of small scale test techniques. Material Science & Engineering A- Struct, 636, 529-535, 2015.
M. Fernández, C. Rodríguez, F.J. Belzunce, T.E. García. Use of small punch test to estimate the mechanical properties of powder metallurgy products employed in the automotive industry. Powder Metallurgy, 58(3), 171-177, 2015.
C. Rodríguez, T.E. García, S. Montes, L. Rodríguez, A. Maestro. In vitro comparison between cortical and cortico-cancellous femoral suspension devices for anterior cruciate ligament reconstruction. Implications for mobilization. Knee Surgery, Sports Traumatology, Arthroscopy, 23(8), 2324-2329, 2014.
P. Sanjurjo, C. Rodríguez , I. Peñuelas, T.E. García, F.J. Belzunce. Influence of the target material constitutive model on the numerical simulation of a shot peening process. Surface & Coatings Technology, 258, 822-831, 2014.