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Title: Effect of carbon and oxygen on microstructure and mechanical properties of Ti-25V-15Cr-2Al (wt%) alloys

Journal Article · · Acta Materialia
; ;  [1]; ;  [2]
  1. Univ. of Birmingham, Edgbaston (United Kingdom)
  2. Rolls-Royce PLC, Derby (United Kingdom)

The effect of carbon additions on microstructure and mechanical properties of alloys with different levels of oxygen was studied in {beta} titanium alloys of the general composition Ti-25V-15Cr-2Al (all compositions are in wt% unless otherwise indicated). The microstructures were studied using optical microscopy (OM), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that titanium carbides with vacancy-ordered structure formed in all alloys with C additions of over 1,000 w.p.p.m. Grains were refined by carbides.Wavelength-dispersive X-ray (WDX) analysis showed that oxygen was much higher in carbides than in {beta} matrix. After long-term exposure at 550 C {alpha} precipitation was significantly reduced in samples with titanium carbides compared with those without. A significant improvement in room temperature tensile ductility was achieved by the addition of carbon to the alloys. Elongations of {approximately} 10% were obtained in samples which were exposed at 550 C for 500 h following heat treatments at 1,050 and 700 C.

OSTI ID:
684391
Journal Information:
Acta Materialia, Vol. 47, Issue 10; Other Information: PBD: 10 Aug 1999
Country of Publication:
United States
Language:
English