Precipitation and martensitic transformation of fcc-Ti in Nb–Ti–Si based ultrahigh temperature alloys

Archives of Metallurgy and Materials

“…Nbss has superior room temperature fracture toughness exceeding 20 MPam 1/2 [8] in comparison with Nb 5 Si 3 phase (2-2.5 MPam 1/2 ) [9]. However, their poor oxidation resistance resulting from Nbss and brittleness of niobium silicide are main drawbacks of their practical application [4,6,10].…”

“…Alloying and processing technologies are two techniques used for solving these problems [6,11]. Many authors have proposed alloying as the most effective, economical and widely used method to improve the properties of niobium silicide based alloys [10][11][12][13]. The influences of Cr [4], Ti [6], Mo [11], B [11], W [11], Al [13], Zn [14], Hf [15] alloying elements on microstructures and mechanical properties of niobium silicide based in-situ composites were reported by many authors.…”

“…Addition of low amounts (less than 5 at. %) of Cr and Al elements contributes to the increase of the high-temperature oxidation resistance [1,10,16]. Mo and W solid solution elements can be used to strengthen the Nb-Si in situ composites.…”

Precipitation behavior of Nb-Si-based in-situ composite manufactured by laser directed energy deposition

“…Being the effective alloying elements to improve the room-temperature fracture toughness and high-temperature oxidation resistance of Nb-Si-based in-situ composite, Ti [3,4], Zr [5,6] and Cr [7,8] have attracted much attentions in recent years. It is found that the precipitation of FCC-Ti [9], Nb5Si3 [10] and Cr2Nb [11] in the Nbss phase could undoubtedly enhance the strength and oxidation resistance of Nb-Si-based in-situ composite. However, the comprehensive investigation into the effects of Ti, Zr and Cr on the precipitation behavior of Nb-Si-based in-situ composite is still lacking.…”