Using quadratic multiple linear regression models to investigate the effect of inoculant type and T6 heat treatment on microstructural, mechanical and corrosion properties of Al-Cu alloy produced by casting

In this study, the effect of different inoculant types such as AlSr10, Al3Ti1B and Al5Ti1B and T6 heat treatment on the microstructure, mechanical properties, and corrosion behavior of Al-5 %Cu alloy were thoroughly investigated. Al-5 % Cu without inoculant, Al-5 %Cu-AlSr10, Al-5 %Cu- Al3Ti1B and Al-5 %Cu- Al5Ti1B alloys were produced by casting, and they were subjected to T6 heat treatment. Microstructures of the alloys were characterized by optical microscopy, SEM with EDX module and XRD. To determine the mechanical properties of the alloys, hardness, tensile and Charpy-V impact tests were applied. Pin on disc and immerse corrosion tests were also carried out to observe grain size effect resulted from different inoculant types on wear and corrosion properties. Sr added Al alloy shows finer grain size than the Al-5 % Cu without inoculant. However, AlSr10 inoculant does not exhibit such good results as compared to Al3Ti1B and Al5Ti1B in terms of grain refinement. When the Al3Ti1B and Al5Ti1B inoculants were compared, 5Ti added one showed finest grains in the structure. In this regard, hardness, tensile strength, and wear resistance were increased systematically with decreasing grain size. Ductility in tensile test and toughness in Charpy-V impact tests of AlSr10 and Al3Ti1B added Al-5 %Cu alloys shows lower value than Al-5 %Cu alloy without inoculant. Corrosion damage increased with decreasing grain size. Further, the statistical performance of these models was tested and the closest model to the measurements was determined. It is expected that the applied quadratic models will be the best option for predicting yield strength, and weight loss in wear and corrosion properties.