Microstructural and fractographic investigation of a centrifugally cast 20Cr32Ni+Nb alloy tube in the ‘as cast’ and aged states

• DOI: 10.1016/j.jmrt.2013.02.006
• Publication Date: 2013-06-14T11:40:50Z
• Authors: Luis Shiguenobu M...; Cláudio Geraldo S...
• Keywords: Dimple; Ductility (Earth science); Elongation; Fractography; Microscale chemistry

Fracture surface and microstructure of tensile samples taken from a centrifugally cast 20Cr32Ni + Nb alloy tube were investigated in the 'as cast' state after being submitted to isochronal aging at temperatures between 670 °C 820 for 200 h. The results show that main crack path is interdendritic macroscopic scale, but fracture characterized by dimples microscale all samples, suggesting micromechanism does not change, spite large ductility loss observed aged (fracture elongation, ε¯f≈0.16, 770 °C) compared with 'as-cast' (ε¯f≈0.42).