Introducing C phase in additively manufactured Ti-6Al-4V: A new oxygen-stabilized face-centred cubic solid solution with improved mechanical properties
“…Thus Ti hydrides can be ruled out here. Of course, a small amount of oxygen can possibly dissolve into the FCC phase [40], as shown in Figure 5(c) due to the rupture of the oxidation film on the surface during UC. Figure 7 FCC phase in UC-Ti confirmed by TEM serial rotation: (a) microstructure of UC-Ti, (b) BF image of a region with a bulk FCC phase, (c) and (d) the corresponding diffraction patterns of [001] to [011] zone axes, (e) BF image of a region with strip-like FCC phase, (f) and (g) diffraction patterns of [001] to [013] zone axes, (h) DF TEM image of FCC phase taken by exciting (131false¯).…”
Section: Resultsmentioning
confidence: 99%
“…Thus Ti hydrides can be ruled out here. Of course, a small amount of oxygen can possibly dissolve into the FCC phase [40], as shown in Figure 5(c) due to the rupture of the oxidation film on the surface during UC.…”
Section: Reconfirmation Of Fcc Phase Formation Induced By Ultrasonic ...mentioning
This paper investigates the microstructural characteristics of Ti layer in ultrasonic additive manufacturing of Ti/Al laminate composites by electron backscattered diffraction and transmission electron microscopy. Results show that a face-centred cubic (FCC) phase is formed in the Ti matrix around the Ti/Al bonding interface, and it keeps (111) fcc (0002) hcp and [011] fcc [2110] hcp orientation relationship with hexagonal close-packed (HCP) Ti matrix. The phase transition from HCP to FCC occurs in the region with high shear strain, which is associated with the movement of Frank or Shockley partial dislocations. The high-volume fraction of FCC-Ti under high ultrasonic amplitude can favour the improvement in the Ti/Al interfacial bonding strength via enhancing the plastic deformability of Ti foil.
“…Thus Ti hydrides can be ruled out here. Of course, a small amount of oxygen can possibly dissolve into the FCC phase [40], as shown in Figure 5(c) due to the rupture of the oxidation film on the surface during UC. Figure 7 FCC phase in UC-Ti confirmed by TEM serial rotation: (a) microstructure of UC-Ti, (b) BF image of a region with a bulk FCC phase, (c) and (d) the corresponding diffraction patterns of [001] to [011] zone axes, (e) BF image of a region with strip-like FCC phase, (f) and (g) diffraction patterns of [001] to [013] zone axes, (h) DF TEM image of FCC phase taken by exciting (131false¯).…”
Section: Resultsmentioning
confidence: 99%
“…Thus Ti hydrides can be ruled out here. Of course, a small amount of oxygen can possibly dissolve into the FCC phase [40], as shown in Figure 5(c) due to the rupture of the oxidation film on the surface during UC.…”
Section: Reconfirmation Of Fcc Phase Formation Induced By Ultrasonic ...mentioning
This paper investigates the microstructural characteristics of Ti layer in ultrasonic additive manufacturing of Ti/Al laminate composites by electron backscattered diffraction and transmission electron microscopy. Results show that a face-centred cubic (FCC) phase is formed in the Ti matrix around the Ti/Al bonding interface, and it keeps (111) fcc (0002) hcp and [011] fcc [2110] hcp orientation relationship with hexagonal close-packed (HCP) Ti matrix. The phase transition from HCP to FCC occurs in the region with high shear strain, which is associated with the movement of Frank or Shockley partial dislocations. The high-volume fraction of FCC-Ti under high ultrasonic amplitude can favour the improvement in the Ti/Al interfacial bonding strength via enhancing the plastic deformability of Ti foil.
“…b-C 3 N 4 has a shorter carrier lifetime due to the fact that the accelerating electric field generated by BIT after physical adsorption facilitates the transfer of the carriers, thus enhancing the photocatalytic hydrogen evolution reaction. 52…”
The surface modification technique based on BIT physisorption and K+ doping results in an extremely high hydrogen production efficiency of carbon nitride, up to 21.35 mmol g−1 h−1.
“…This work found an unexpected face-centered cubic (FCC) phase in the manufactured specimens. No FCC phase is located on the titanium phase diagram because these diagrams only show equilibrium phases [17,18]. At high temperatures, there exists a body centered cubic (BCC) phase designated as Ti-β, while at lower temperatures, a stable hexagonal close packed phase (HCP) forms as Ti-α [19,20].…”
Section: Introductionmentioning
confidence: 99%
“…FCC phases have been reported in CpTi and Ti-alloys [18][19][20][21][22][23][24], and some reports on FCC forming in additive processed specimens [17,25]. It has been described that the FCC phase impacts mechanical performance [17,25].…”
Metal additive manufacturing is a developing technique with numerous advantages and challenges to overcome. As with all manufacturing techniques, the specific raw materials and processing parameters used have a profound influence on microstructures and the resulting behavior of materials. It is important to understand the relationship between processing and microstructures of Ti to advance knowledge of Ti-alloys in the additive field. In this study, a face-centered cubic (FCC) phase was found in grade 2 commercially pure titanium specimens, additively manufactured with directed energy deposition in an argon atmosphere. Two scanning speeds (500 and 1000 mm/min) and three scanning patterns (cross-hatched and unidirectional patterns) were investigated. Electron backscatter diffraction and energy-dispersive X-ray spectroscopy were used for microstructural and compositional analysis. Inverse pole figure, phase, and kernel average misorientation (KAM) maps were analyzed in this work. Larger amounts of the FCC phase were found in the unidirectional scanning patterns for the slower scanning speed, while the cross-hatched pattern for both scanning speeds showed a lower amount of FCC. Higher KAM averages were present in the faster scanning speed specimens. According to EDS scans, small amounts of nitrogen were uniformly distributed throughout the specimens, leading to the possibility of interstitial content as a contributing factor for development of the observed FCC phase. However, there is no clear relationship between nitrogen and the FCC phase. The formation of this FCC phase could be connected to high densities of crystalline defects from processing, plastic deformation, or the distribution of interstitials in the AM structure. An unexpected Kurdjumow–Sachs-type orientation relationship between the parent beta phase and FCC phase was found, as 110BCC∥111FCC, 111BCC∥110FCC.
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