Design of quaternary Ir-Nb-Ni-Al refractory superalloys

Yu, Xihong; Yamabe‐Mitarai, Yoko; Ro, Y.; Harada, Hiroshi

doi:10.1007/s11661-000-0063-9

Cited by 42 publications

(22 citation statements)

References 4 publications

(3 reference statements)

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“…Appropriate alloying and heat treatment of these so-called refractory superalloys should lead to a fine distribution of a coherently embedded ␥Ј phase with L1 2 structure. [2][3][4][5][6][7][8][9][10][11][12][13][14] A major drawback of Ir and Rh alloys is their brittleness. [15] Hill and co-workers conducted an extensive assessment of systems with Pt as the major constituent.…”

Section: Introductionmentioning

confidence: 99%

Stabilizing the L12 structure of Pt3Al(r) in the Pt-Al-Sc system

Völkl

Yamabe‐Mitarai

Huang

et al. 2005

Metall Mater Trans A

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The Pt-Al system has high potential to act as alloy base for so-called refractory superalloys. Although the envisaged strengthening phase Pt 3 Al(r) has favorable L1 2 crystal structure only at high temperatures, even small amounts of Sc stabilized L1 2 crystal structure at low temperature. Pt-Al-Sc alloys were arc melted, heat treated, and examined by means of scanning electron microscopy and X-ray diffraction (XRD). Pt 3 Al 1Ϫx Sc x (r) forms a continuous phase field from the Al-rich side to the Sc-rich side of the Pt-Al-Sc ternary system. The absolute value of the lattice misfit between cubic Pt 3 Al 1Ϫx Sc x (r) and the matrix decreases with increasing Sc content.

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Section: Introductionmentioning

confidence: 99%

Stabilizing the L12 structure of Pt3Al(r) in the Pt-Al-Sc system

Völkl

Yamabe‐Mitarai

Huang

et al. 2005

Metall Mater Trans A

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“…Platinum has similar chemistry to nickel and so reacts similarly with the alloying elements and has been investigated as a potential substitute in higher temperature alloys in even more aggressive environments (Coupland et al., 1980; Fischer et al, 1997 Fischer et al, , 1999a Fischer et al, , 1999b Fischer et al, , 2001Völkl et al, 2000;Wolff and Hill, 2000). The potential of using an fcc PGM analogue was mooted several times (Bard et al, 1994), in NIMS, Japan owing to the good properties of iridium-based and rhodium-based alloys (Yamabe et al, 1996(Yamabe et al, , 1997(Yamabe et al, , 1998a(Yamabe et al, , 1998b(Yamabe et al, , 1999Yu et al, 2000), Pt-Ir alloys (YamabeMiterai et al, 2003), Pt-Al-Nb and Pt-Al-Ir-Nb alloys (Huang et al, 2004) and platinum-based alloys in South Africa (Wolff and Hill, 2000). The PGMs and nickel have similar structures (mostly fcc) and similar chemistries for the formation of similar phases.…”

Section: * Dst-nrf Centre Of Excellence In Strong Materialsmentioning

confidence: 99%

PGMs: A cornucopia of possible applications

Cornish¹

2017

J. South. Afr. Inst. Min. Metall.

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South Africa has been mining PGMs for many years and has a vested interest in the usefulness of these metals, although originally, there was little thought about downstream beneficiation and some of the products were later purchased, in effect repurchasing the raw materials. However, for about 20 years, it has been realised that in order to build wealth sustainably, at least some of the beneficiation and development has to be done in South Africa. This is because for each stage of beneficiation, the value of the commodity increases and so to buy the PGMs back in a later state is uneconomical. Also, the industries need to be established here in South Africa, so that South Africans can work in them and become part of the workforce and generate their own wealth and sustainability for their families. This is part of the rationale of the AMI.In order to drive this, as well as a viable commercial strategy, with viable and wanted products, there has to be something different in the production mixture, for example, the product has to be better, new or cheaper. This is where research is used to try and develop new capabilities, or to improve them. PGMs, application, product development. PGMs: A cornucopia of possible applications and thermal conductivity of Pt are important (Fischer, 1992). Mechanically, Pt alloyed with rhodium or iridium combine high ductility with adequate creep strength and these properties give the alloys potential for applications in the chemical, space technology and glass industries (Fischer, 2001;Whalen, 1988; Lupton, 1990). In the spacecraft industry, PGMs are used to increase the heat resistance of rocket engine nozzles. A very important application is the manufacture of high-purity optical glasses and glass fibres by using platinum-containing tank furnaces, stirrers and feeders to withstand the high temperatures, mechanical loads and corrosive attack under the glass manufacturing and shaping conditions. In glasses, outstanding purity, homogeneity and the absence of bubble inclusions can be achieved only by using platinum alloys. If ceramic melting vessels were used, ceramic particles would be loosened by erosion, which would contaminate the glass melts and so compromise the desired optical properties such as transmittance. The alloys are expensive, but there are very few other materials that could replace platinum without risk of compromising the product. Thus, this is a valuable and safe use for platinum and some of its alloys. * DST-NRF Centre of Excellence in Strong MaterialsAnother 'standard use' of PGMs is in thermocouples and this arises because of their high electrical and thermal conductivity, as well as stability due to their high corrosion resistance. Typical alloys are Pt-Rh and Pt-Ru. The thermocouples do eventually degrade in aggressive environments and become brittle, but usually without much impairment of the electrical and conductive properties.A long-standing use of PGMs is in catalysts and South Africa has established an autocatalyst manufacturing and refurbishment plant for...

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“…The alloy compositions and phases determined are listed in Table I. [8][9][10][11][12][13][14] The established schematic phase diagram is shown in Figure 1, [14] in which four single-phase regions of one fcc, two L1 2 , and one B2 were determined. The fcc and B2 phases formed a continuous solid solution from the Ir-rich side to the Ni-rich side of the Ir-Nb-Ni-Al tetrahedron.…”

Section: A the Phase Relationshipmentioning

confidence: 99%

Partial phase relationships in Ir-Nb-Ni-Al and Ir-Nb-Pt-Al quaternary systems and mechanical properties of their alloys

Yamabe‐Mitarai

Nakazawa

Harada

et al. 2005

Metall Mater Trans A

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Two quaternary systems, Ir-Nb-Ni-Al and Ir-Nb-Pt-Al, were successively investigated to assess their possible use in ultra-high-temperature applications. The phase relationships concentrated on the fcc/L1 2 two-phase region were primarily established, and the mechanical properties were studied. Ir-Nb-Ni-Al quaternary alloys around the Ir-rich or Ni-rich corners of the Ir-Nb-Ni-Al tetrahedron showed a coherent fcc/L1 2 two-phase structure, analogous to that of Ni-base superalloys; however, most of the alloys presented three or four phases with two types of L1 2 phases. Although these alloys showed a high compressive strength at high temperature, they exhibited a higher creep rate than Ir-base binary and ternary alloys. Another quaternary system, Ir-Nb-Pt-Al, showed promising results. Only an fcc/L1 2 two-phase structure was found in all the alloys investigated with compositions ranging from the Ir-rich side to the Pt-rich side, and the lattice misfit between the fcc and L1 2 phases was small. The high-temperature strength at 1200 °C of Ir-Nb-Pt-Al alloys was higher than that of Ir-Nb-Ni-Al alloys with the same Ir content (at. pct). Moreover, Ir-Nb-Pt-Al alloys exhibited excellent creep resistance at 1400 °C and 100 MPa.

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Design of quaternary Ir-Nb-Ni-Al refractory superalloys

Cited by 42 publications

References 4 publications

Stabilizing the L12 structure of Pt3Al(r) in the Pt-Al-Sc system

Stabilizing the L12 structure of Pt3Al(r) in the Pt-Al-Sc system

PGMs: A cornucopia of possible applications

Partial phase relationships in Ir-Nb-Ni-Al and Ir-Nb-Pt-Al quaternary systems and mechanical properties of their alloys

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