Titanium and Titanium Alloy via Sintering of TiH&lt;sub&gt;2&lt;/sub&gt;

Wang, Hong Tao; Lefler, M. N.; Fang, Zhigang Zak; Lei, Ting; Fang, Shu Ming; Zhang, Jia Min; Zhao, Qun

doi:10.4028/www.scientific.net/kem.436.157

Cited by 66 publications

(32 citation statements)

References 8 publications

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“…However, it should be noted that the ex-situ XRD and TEM investigations may suffer from instant information loss in terms of the phase transformation during the heating process [19,27,30,46,47]. Additionally, although in situ high temperature XRD and X-ray synchrotron/neutron diffraction techniques were applied, their results may still be of concern.…”

Section: Dehydrogenation Processmentioning

confidence: 99%

An in situ Study of NiTi Powder Sintering Using Neutron Diffraction

Chen

Liss

Cao

2015

Metals

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This study investigates phase transformation and mechanical properties of porous NiTi alloys using two different powder compacts (i.e., Ni/Ti and Ni/TiH2) by a conventional press-and-sinter means. The compacted powder mixtures were sintered in vacuum at a final temperature of 1373 K. The phase evolution was performed by in situ neutron diffraction upon sintering and cooling. The predominant phase identified in all the produced porous NiTi alloys after being sintered at 1373 K is B2 NiTi phase with the presence of other minor phases. It is found that dehydrogenation of TiH2 significantly affects the sintering behavior and resultant microstructure. In comparison to the Ni/Ti compact, dehydrogenation occurring in the Ni/TiH2 compact leads to less densification, yet higher chemical homogenization, after high temperature sintering but not in the case of low temperature sintering. Moreover, there is a direct evidence of the eutectoid decomposition of NiTi at ca. 847 and 823 K for Ni/Ti and Ni/TiH2, respectively, during furnace cooling. The static and cyclic stress-strain behaviors of the porous NiTi alloys made from the Ni/Ti and Ni/TiH2 compacts were also investigated. As compared with the Ni/Ti sintered samples, OPEN ACCESSMetals 2015, 5 531 the samplessintered from the Ni/TiH2 compact exhibited a much higher porosity, a higher close-to-total porosity, a larger pore size and lower tensile and compressive fracture strength.

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Section: Dehydrogenation Processmentioning

confidence: 99%

An in situ Study of NiTi Powder Sintering Using Neutron Diffraction

Chen

Liss

Cao

2015

Metals

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“…The use of hydrogenated Ti powder instead of metallic Ti powder has been shown to result in reduced oxygen content in the sintered alloy (see section 'Vacuum sintering TiH 2 ') [170,171]. Additionally, the brittleness of Ti hydride results in a tendency of the powder to crush during cold compaction [172,173]. This has been shown to result in better green density over Ti powder of similar particle size and morphology when using the same compaction pressures.…”

Section: Sintering Of Tihmentioning

confidence: 99%

“…Since 2011, a process called HSPT has been developed by Fang, Sun, and Paramore et al [4,172,174,[202][203][204][205][206][207][208][209][210][211][212][213] HSPT is a multi-step pressureless sintering process, in which Ti hydride or partially hydrogenated Ti powder is blended with master-alloy or elemental powders and sintered under a dynamically controlled hydrogen atmosphere. After sintering, residual hydrogen is removed by annealing under vacuum or inert gas ( Figure 21).…”

Section: Sintering Of Tih 2 In Hmentioning

confidence: 99%

Powder metallurgy of titanium – past, present, and future

Fang

Paramore

Sun

et al. 2017

International Materials Reviews

389

158

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Powder metallurgy (PM) of titanium is a potentially cost-effective alternative to conventional wrought titanium. This article examines both traditional and emerging technologies, including the production of powder, and the sintering, microstructure, and mechanical properties of PM Ti. The production methods of powder are classified into two categories: (1) powder that is produced as the product of extractive metallurgy processes, and (2) powder that is made from Ti sponge, ingot, mill products, or scrap. A new hydrogen-assisted magnesium reduction (HAMR) process is also discussed. The mechanical properties of Ti-6Al-4V produced using various PM processes are analyzed based on their dependence on unique microstructural features, oxygen content, porosity, and grain size. In particular, the fatigue properties of PM Ti-6Al-4V are examined as functions of microstructure. A hydrogen-enabled approach for microstructural engineering that can be used to produce PM Ti with wroughtlike microstructure and properties is also presented.

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“…As shown by review/overview articles, [1][2][3][4] the newly developed low cost titanium/titanium alloy powder production techniques such as the Armstrong and hydrogenation-dehydrogenation (HDH) processes in combination with PM processes will likely lead to cost effective production of titanium/titanium alloy bulk materials and near-net-shaped components. Wang et al [5] and Abakumov et al [6] showed that using titanium hydride (TiH 2 ) powder they can accelerate the sintering process of titanium and titanium alloy powders. Bolzoni et al [7] also showed that using HDH titanium powder it is more favorable than using titanium sponge fine powder in terms of mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

The Tensile Mechanical Properties of Thermomechanically Consolidated Titanium at Different Strain Rates

Liang

Jia

et al. 2015

Metall Mater Trans A

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The microstructures, tensile mechanical properties, and fracture behavior of a commercially pure (CP) titanium disk (called PF/Ti disk) and a CP titanium bar (called PE/Ti bar) made by powder compact forging (PCF) and powder compact extrusion (PCE) respectively have been studied. With increasing the strain rate from 10 À4 to 10 À1 s À1 , the yield strength of the PF/Ti disk and PE/Ti bar increased from 708 to 811 MPa and from 672 to 764 MPa, respectively; their UTS increased from 824 to 1009 MPa and from 809 to 926 MPa, respectively, and their elongation to fracture decreased from 21 to 8 pct and from 25 to 17.8 pct, respectively. With a low strain rate of 10 À4 s À1 , the PF/Ti disk did not show any cavities at unbonded or weakly bonded interparticle boundaries, but the PE/Ti bar showed a small number of cavities with sizes of around 1 lm. With a high strain rate of 10 À2 s À1 , the PF/Ti disk showed a small number of cavities with sizes in the range of 0.1 to 0.5 lm, while for the PE/Ti bar, the cavities grew into microcracks of up to 20 lm long. The findings suggest that close to 100 pct of consolidation is rapidly achieved by PCF at 1573 K (1300°C) and PCE at 1523 K (1250°C), respectively, possibly due to the dissolution of the particle oxide surface films during heating and rapid diffusion bonding between the fresh particle surfaces during PCF and PCE.

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Titanium and Titanium Alloy via Sintering of TiH<sub>2</sub>

Cited by 66 publications

References 8 publications

An in situ Study of NiTi Powder Sintering Using Neutron Diffraction

An in situ Study of NiTi Powder Sintering Using Neutron Diffraction

Powder metallurgy of titanium – past, present, and future

The Tensile Mechanical Properties of Thermomechanically Consolidated Titanium at Different Strain Rates

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