Additive manufacturing (AM) is a highly innovative method for joining dissimilar materials for industrial applications. In the present work, AM of STS630 and Ti-6Al-4V powder alloys on medium entropy alloys (MEAs) NiCrCo and NiCrCoMn is studied. The STS630 and Ti64 powders are deposited on the MEAs. Joint delamination and cracks are observed after the deposition of Ti64 on the MEAs, whereas the deposition of STS630 on the MEAs is successful, without any cracks and joint delamination. The microstructure around the fusion zone interface is characterized by scanning electron microscopy and X-ray diffraction. Intermetallic compounds are formed at the interfacial regions of MEA-Ti64 samples. In addition, Vicker’s hardness value increased dramatically at the joint interface between MEAs and Ti-6Al-4V compared to that between MEAs and STS630. This result is attributed to the brittle nature of the joint, which can lead to a decrease in the joint strength.

Microstructural examination of the Nb-Si-B alloys at Nb-rich compositions is performed. The Nb-rich corner of the Nb-Si-B system is favorable in that the constituent phases are Nb (ductile and tough phase with high melting temperature) and T₂ phase (very hard intermetallic compound with favorable oxidation resistance) which are good combination for high temperature structural materials. The samples containing compositions near Nb-rich corner of the Nb- Si-B ternary system are prepared by spark plasma sintering (SPS) process using T₂ and Nb powders. T₂ bulk phase is made in arc furnace by melting the Nb slug and the Si-B powder compact. The T₂ bulk phase was subsequently ballmilled to powders. SPS is performed at 1300°C and 1400°C, depending on the composition, under 30 MPa for 600s, to produce disc-shaped specimen with 15 mm in diameter and 3 mm high. Hardness tests (Rockwell A-scale and micro Vickers) are carried out to estimate the mechanical property.

Citations

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• Fabrication of Nb-Si-B Alloys Using the Pulverized Nb-T₂ Alloy Powder
  Min-Ho Cho, Sung-Jun Kim, Hyun-Ji Kang, Sung-Tag Oh, Young Do Kim, Seong Lee, Myung Jin Suk
  Journal of Korean Powder Metallurgy Institute.2019; 26(4): 299.     CrossRef
• Mechanical properties of Mo-Nb-Si-B quaternary alloy fabricated by powder metallurgical method
  Jong Min Byun, Su-Ryong Bang, Se Hoon Kim, Won June Choi, Young Do Kim
  International Journal of Refractory Metals and Hard Materials.2017; 65: 14.     CrossRef
• Mechanical properties of Mo-Si-B alloys fabricated by using core-shell powder with dispersion of yttria nanoparticles
  Jong Min Byun, Su-Ryong Bang, Won June Choi, Min Sang Kim, Goo Won Noh, Young Do Kim
  Metals and Materials International.2017; 23(1): 170.     CrossRef
• Fabrication of Ta2O5 Dispersion-Strengthened Mo-Si-B Alloy by Powder Metallurgical Method
  Jong Min Byun, Won June Choi, Su-Ryong Bang, Chun Woong Park, Young Do Kim
  JOM.2017; 69(4): 683.     CrossRef
• Rapid consolidation of nanostuctured WC-FeAl3 by pulsed current activated heating and its mechanical properties
  In-Jin Shon, Seok-Jae Lee
  International Journal of Refractory Metals and Hard Materials.2017; 65: 69.     CrossRef