Measurement of residual stresses and distortion in rapidly quenched components

dc.creatorAplitsiotis, Nikolaos Engineeringen_US
dc.description.abstractUnacceptable distortion and residual stresses can occur during the manufacturing of solution heat-treated 2xxx aluminum alloys. Rapid quenching rates are being used to improve mechanical properties by inducing percepitation hardening but they result in high thermal stresses, which cause severe distortion and high levels of residual stresses. Under these circumstances, adjacent sheets may come in contact with one another, either during quenching or during handling, resulting in a poor surface finish, which renders the material useless. Therefore, it is desirable to develop a quenching process that maximizes the material properties, while minimizing the distortion and residual stresses. This investigation studied the effect of quenching media, holding mechanism, and immersion rate on the distortion and residual stresses of rapidly quenched aluminum 2024 sheets. In addition, a thermal characterization of the quenching process was performed using a specially designed "thermal" specimen to collect time temperature data and run an inverse heat transfer code to predict surface temperature, cooling rate, and heat flux variation along the surface. An experimental procedure for collecting time temperature data was established and experiments were performed using water and 40% UCON Quenchant A as quenching media. Water quenching resulted in much higher cooling rate, greater heat flux variation, and minimized the cooling time to maximum cooling rate when compared to 40% UCON Quenchant A.
dc.publisherTexas Tech Universityen_US
dc.subjectAlloys -- Thermal propertiesen_US
dc.subjectAluminum alloys -- Heat treatmenten_US
dc.titleMeasurement of residual stresses and distortion in rapidly quenched components