![]() ![]() However, diffraction techniques can evaluate the level of residual stress by measuring the level of deformation. Therefore, it cannot be directly measured. Residual stress is an extrinsic property of a material. Therefore, it is important to know how different thermomechanical processes affect the level of residual stress in the material. The combination of these effects in a multi-phase material might contribute to its sudden failure in service, once each phase has its own physical and mechanical properties. Thermomechanical processes such as heating, forming, and welding, contribute to non-uniform plastic deformations due to misfiting between different parts of a component and/or metallurgical phenomena occurring into the material structure (phase precipitation/dissolution, grain shape modifications, dislocation generation/aniquilation, etc.,). The combination of the residual stress and the loading in service can be detrimental to the component performance. ![]() Despite the efforts to control manufacturing parameters to guarantee an optimal microstructure, all materials present some level of residual stress. According to previous work, heating and rolling processes alter the microstrucure of the 6061 alloy and, consequently, its corrosion resistance and strength. Thermomechanical processes are responsible for modifications in microstructure features of the Al alloys. As it can be seen, different thermomecanical processes can be adopted in order to obtain suitable alloy properties depending on their application. On the other hand, the O temper corresponds to the annealed condition to obtain the lowest strength temper, being extremely ductile and suitable for forming process. This alloy might be used when strengthening is a requirement. It involves a solution heat treatment step, followed by quenching and aging in the 175–180 ☌ range for 10–20 h. The 6061-T6 temper is the peak-aged condition of this alloy. It precipitates at temperatures in the range from 125 to 200 ☌. This phase has a needle-like morphology, coherent with the matrix and aligned parallel to α. The good mechanical properties of this alloy are related to precipitation hardening resulting mainly from the "β″ (Mg 5Si 6) phase. The 6061 aluminum alloy is widely used in the automotive, offshore, aircraft, construction and nuclear industries due to its good mechanical properties and corrosion resistance compared to other Al series alloys. Moreover, the RSND technique allows observing that the texture is also higher for the samples processed by the nuclear thermomechanical process due the hot rolling stage. The nuclear thermomechanical processes, R3 and R9H60, resulted in increased level residual stress related to the T6 and showed a tensile nature in relation to its parent material (6061-O). The O temper was the only condition which showed compressive residual stress and the most coarsened precipitates. This was associated with the highest microhardness value (highest density of "β″ phase) and lowest grain size. The results showed that the lowest level of residual stress was found for the peak age, T6 condition. Commercial tempers such as T6 (peak aged) and O (annealed) were compared with the 6061 alloy after different steps of a thermomechanical processing used for the manufacturing of nuclear fuel plates, R3 and R9H60. In this study the internal level of the residual stress of a 6061 Al–Mg–Si alloy with different thermomechanical processes was evaluated by residual stress neutron diffraction (RSND). We can measure components such as rolls, shafts, plates and castings as well as additive manufactured components.Depending on the nature of the loading during service, the level and nature of residual stress can contribute to the lower service-life of a component. Hole drilling: We measure residual stresses in accordance with ASTM standard E 837 ”Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method”. We dispose a number of XRD-systems, which are portable and allows for field measurements. X-ray diffraction (XRD): We are accredited for XRD measurements in accordance with SS-EN-15305:2008 "Non-destructive Testing - Test Method for Residual Stress analysis by X-ray Diffraction". Residual stresses will impact the fatigue life of metallic components, these may be favorable (compressive) or unfavorable (tensile). Residual stresses develops and alters throughout the whole component manufacturing route, that is during casting, rolling, forging, heat treatment and machining. This is done by measuring residual stresses of components and test pieces using XRD- or hole drilling techniques. RISE measure and analyze residual stresses and how they are altered by various production processes with the purpose to improve, verify or increase knowledge on how process parameters affects residual stresses. ![]()
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