The present work correlates the quasi-static, tensile mechanical properties of additively manufactured Ti-6Al-4V extra low interstitial (ELI, Grade 23) alloy to the phase constituents, microstructure, and fracture surface characteristics that changed with post-heat treatment of stress relief (670 °C for 5 h) and hot isostatic pressing (HIP with 100 MPa at 920 °C for 2 h under an Ar atmosphere). Ti-6Al-4V ELI alloy tensile specimens in both the horizontal (i.e., X and Y) and vertical (Z) directions were produced by the laser powder bed fusion (LPBF) technique. Higher yield strength (1141 MPa), higher tensile strength (1190 MPa), but lower elongation at fracture (6.9%), along with mechanical anisotropy were observed for as-stress-relieved (ASR) samples. However, after HIP, consistent and isotropic mechanical behaviors were observed with a slight reduction in yield strength (928 MPa) and tensile strength (1003 MPa), but with a significant improvement in elongation at fracture (16.1%). Phase constituents of acicular α′ phase in ASR and lamellar α + β phases in HIP samples were observed and quantified to corroborate the reduction in strength and increase in ductility. The anisotropic variation in elongation at fracture observed for the ASR samples, particularly built in the build (Z) direction, was related to the presence of “keyhole” porosity.

Laser powder bed fusion (LPBF) is a popular additive manufacturing (AM) technique that has demonstrated the capability to produce sophisticated engineering components. This work reports the crack-free fabrication of an SS316L/IN718 bimetallic structure via LPBF, along with compositional redistribution, phase transformations and microstructural development, and nanohardness variations. Constituent intermixing after LPBF was quantitatively estimated using thermo-kinetic coefficients of mass transport and compared with the diffusivity of Ni in the austenitic Fe-Ni system.

AZ91, AZ91-0.5B and AZ91-1.0B magnesium alloys are produced in an inert atmosphere to investigate the influence of B on microstructure and properties of AZ91 alloy. Microstructural study is carried out using optical microscopy. Microhardness measurements are conducted by Vickers hardness tester. Using a pin-on-disk type apparatus, wear tests are conducted under dry sliding condition to assess the beneficial effect of boron on the wear properties of AZ91 alloy in relation to the resulted hardness and microstructures. The worn surface and wear particles morphology are also investigated. It is observed from microstructural investigation that the grains become finer with the addition of boron. The hardness is also found to increase with the addition of boron in AZ91 alloy, however maximum hardness is achieved with the addition 0.5 % B addition. The wear resistance is found to be better in the boron added alloy and maximum resistance is found with the addition of 0.5 % B. Wear mechanisms are also investigated.