Influence of Substitution of Fe by Mo on Heat Treatment Behavior in Ti-Mo-Fe Alloys

Abstract:

In order to reduce the cost of β-type Ti alloys, the use of Fe as an alloying element has been studied. However, Fe is known to have a very high diffusion coefficient in β-Ti of about 2.6×10^-12 m²/s at 1200 K, and its behavior during heat treatment is expected to be difficult to control. By contrast, Mo, which is also a β-stabilizing element, has a diffusion coefficient of only about 2.5×10^-14 m²/s at 1200 K, i.e., roughly 100 times smaller than that of Fe^{1), 2)}. In this study, the effect of the partial substitution of Fe with Mo on the aging behavior of β-Ti alloys was investigated using X-ray diffraction, electric resistivity, and Vickers hardness measurements. Ti-Mo-Fe alloys were solution-treated by holding at 1173 K for 3.6 ks and then quenching in ice water. In the X-ray diffraction patterns for the resulting samples, only peaks associated with the β phase were identified. It was found that the electrical resistivity and Vickers hardness decreased with increasing Mo content. As the Mo-to-Fe ratio increased, the decrease in electrical resistivity and the increase in Vickers hardness occurred later during the isothermal aging process. This was due to a delay in isothermal ω-phase precipitation.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 162-169
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.162
• Online since: January 2021
• Authors: Kyosuke Mizuta*, Shotaro Miyake, Masahiko Ikeda, Masato Ueda
• Keywords: Diffusion Rate, Electrical Resistivity, Titanium Molybdenum Iron Alloy, Vickers Hardness, X-Ray Diffraction Measurements

References

[1] A.E. Pontau and D. Lazarus: Phys. Rev., Diffusion of titanium and niobium in bcc Ti-Nb alloys, 19 (1979), 4027-4037.

DOI: 10.1103/physrevb.19.4027

[2] Hideki Nakajima and Masahiro Koiwa: Diffusion in Titanium, Bulletin of JIM.

[3] 30(1991), 526-535.

[4] M.Ikeda and M.Ueda: Materials Research Innovations, Influence of partial substitution of V with Cr on phase constitution and heat treatment behavior of Ti-Cr-V-Al alloys.

DOI: 10.1179/1432891713z.000000000299

[5] 17 (2013), SUPPL 2, S2-100 ~ S2-105.

[6] P.Markovsky, M.Ikeda and V.I. Bondarchuk: Microstructure and Mechanical Properties of.

[7] a New Ti-1.5Al-1Fe-7.2Cr Alloy Produced with Conventional Cast and Wrought Approach, Metallofiz. Noveishie Tekhnol, 41 (2019), pp.2321-2330.

[8] Masahiko Ikeda, Shin-ya Komatsu, Takashi Sugimoto, Kiyoshi Kamei: Anormal Temperature Dependence of Resistivity in Ti-Mo Binary Alloys, J. Japan Inst. Metals, Vol. 52, No. 2 (1988), pp.144-149.

DOI: 10.2320/jinstmet1952.52.2_144

[9] Shin-ya Komatsu, Masahiko Ikeda, Takashi Sugimoto, Kiyoshi Kamei, Kou Ichiro: Phase Constitution and Resistivity of Quenched Ti-2 to 15 mass% Fe alloys, J. Japan Inst. Metals, Vol. 55, No. 5 (1991), pp.491-496.

DOI: 10.2320/jinstmet1952.55.5_491