The stress state-dependent fracture behavior of binder jetted 316L stainless steel infiltrated with bronze (SS316 + bronze) with varying porosity and secondary phases was investigated. Notched tension specimens were fabricated to probe mechanical behavior under stress triaxialities ranging from approximately 0.5 to 0.8. Variations in porosity and secondary phases were studied by performing bronze infiltration in different N2- and Ar-based atmospheres. All samples infiltrated in N2-based atmospheres had (Cr, Mo)2N precipitates whereas samples infiltrated in the Ar-based atmosphere had (Cr, Mo)7C3 precipitates. Internal porosity was assessed using x-ray computed tomography (XCT) and ultrasonic attenuation and wave speed measurements. Finite element simulations were performed to determine the stress state-dependent strains to failure of samples, which were linked to nondestructive evaluation signals. Ultrasonic signals were found to correlate to pore volume fraction from XCT and mechanical properties, with attenuation being inversely correlated, and wave speed being positively correlated, with strength and ductility. The ductility of the samples was inversely correlated to stress triaxiality and porosity. In samples with similar porosities but infiltrated in different environments, the higher fraction of (Cr, Mo)2N in samples infiltrated in N2-based atmospheres led to increased strength and reduced ductility compared to those infiltrated in the Ar-based atmosphere.
All Science Journal Classification (ASJC) codes
- General Materials Science
- General Engineering