Effect of Cold-rolled Deformation on the Microstructure and Properties of GH4169 Alloy for Nuclear Power

The effect of different deformation on the microstructure evolution and properties of 5.3 mm thick GH4169 alloy plate was studied. The grain size and grain boundary characteristics were observed by optical microscope and EBSD analysis. The tensile strength， plasticity and other mechanical properties of the materials treated with two deformation amounts were compared， and the relationship between processing， microstructure and properties was established. The results show that the grain size and microstructure are significantly affected by different deformation amounts. Hot rolled plate after process A cold deformation （（thickening1.4 mm） of the grain size is 6 μ m， the small angle grain boundary （<10°） is 73.2%， the large angle grain boundary （> 10 °） is 26.8%， too fast deformation rate makes uneven deformation， the formation of mixed crystal， the proportion of deformation grain is 85.3%， substructure is 5.6%， recrystallization grain rate is 9.1%， After cold deformation of process B （0.7 mm thickening）， the grain size is 35 μ m， the proportion of small angle grain boundary （<10 °） is 51.6%， and the proportion of the large angle grain boundary （> 10 °） is 48.4%， the microstrusture is uniform， the proportion of twins is large， the substructure is 95.7%， the deformed grain is 3.4%， and the recrystallization grain proportion is 0.9%. The room temperature tensile strength and yield strength of cold deformation process A are significantly higher than that of cold deformation process B， but the elongation rate is lower than process B， and the properties of the final plate is attributed to the smaller grain size and higher substructure density of process A.