Bending Ductility Research Articles

Thermal and mechanical properties of amorphous Zr 65Al 7.5Ni 10Cu 12.5Ag 5 alloy containing nanocrystalline compound particles

The thermal and mechanical properties of an amorphous Zr 65Al 7.5Ni 10Cu 12.5Ag 5 alloy containing nanocrystalline compound phase were investigated. The Zr 3Al 2 phase with a spherical shape has a fine size of about 20 nm and is dispersed homogeneously at an interparticle spacing of about 30 nm in an amorphous matrix. The crystallization onset temperature and supercooled liquid regions decrease significantly with an increasing precipitation amount of Zr 3Al 2 phase, indicating an enhancement of thermal instability. This instability is presumably due to the change of the bonding nature among constituent atoms. The maximum tensile fracture strength (2070 MPa) of this mixed phase alloy is much higher than that (1200 MPa) for the amorphous single phase alloy with the same composition. Meanwhile, the good bending ductility of this alloy remains unchanged. Then, the fracture mode in the maximum tensile fracture strength was the shear type among the maximum shear plane. The significant increase of the tensile fracture strength is possibly due to the role of the nanoscale Zr 3Al 2 particles as an effective barrier to suppress shear sliding of the amorphous matrix.

Effects of Titanium Addition on the Microstructure and Mechanical Behavior of Iron Aluminide Fe<SUB><B>3</B></SUB>Al

The microstructure, mechanical properties and deformation behavior of four Fe 3 Al-based alloys containing 0, 5, 10 or 15 at%Ti were investigated. With the addition of Ti, the coarse-grained microstructure of Fe 3 Al was refined and the degree of D0 3 ordering was decreased. Poor bending ductility and a change of fracture mode from cleavage to mixture of intergranular and cleavage were observed in Ti-added alloys. It was shown that the Ti addition decreased the room temperature yield strength, but increased the yield strength at elevated temperatures. Anomalous temperature dependence of yield strength was observed in all the alloys, and the peak strength was shifted to higher temperatures with increasing Ti content. The Ti addition was also revealed to decrease the strain rate sensitivity Curd activation energy for high temperature deformation, Finally, hot working conditions for the Ti-added Fe 3 Al alloys were proposed by taking the stress-strain response, strain rate sensitivity and deformation microstructure into account.

The cause of loss of lithospheric rigidity in areas far from plate tectonic activity

Significant losses of lithospheric strength are generally considered to be almost entirely associated with abnormal heating or steep lithospheric bending and/or stretching near to active plate boundaries. Several areas—the western Greater Caucasus, the North Crimean basin, the Carpathian foredeep, the Peri‐Caspian basin and the Trans‐Caspian areas—are shown to have steep basement slopes, usually comprising a difference in height of several kilometres over lateral distances of only 20–30 km, corresponding to very low, ∼3–5 km, effective elastic thicknesses of the lithosphere. Each of these areas is shown to have undergone rapid steepening of the basement slope, usually within 1–2 Myr but in up to 10 Myr in some areas. At such times, these localities were far from active plate boundaries and in positions where bending forces could not have been transmitted to them from far‐distant plate activities. Surface and/or subsurface loading can similarly be excluded as mechanisms for such steepening, and there is no apparent outflow of crustal materials into adjacent regions. It is suggested that such rapid subsidence far from plate tectonic activity is caused by rapid increases in the local density of the lithosphere. This could occur as a result of, for example, a gabbro‐eclogite transformation in the lower crust, catalysed by the infiltration of volatiles from the asthenosphere. The resultant contraction of the mafic rocks would be non‐uniform in space and produce high deviatory stresses, reducing the viscosity in the lower crust to ∼ 1023 Pa s. This would result in the rapid subsidence of the top of this layer, accompanied by steep ductile bending of the overlying upper crust. Such steep downwarping of the basement would be accompanied by a similar steepening of the underlying weakened mantle. The formation of such steep slopes thus indicates a weakening of the entire lithospheric layer, most probably due to the infiltration of volatiles from the asthenosphere, and unrelated to coeval plate tectonic activity.

Structure and Mechanical Properties of Rapidly Solidified Mg-X Alloys

We have investigated the structure and mechanical properties of binary Mg-X (X=Al, Ca, Li or Zn) melt-spun ribbons in n as-quenched and annealed states as the first step of the development of alloy compositions for new Mg-based rapidly solidified powder metallurgy (RS P/M) alloys. The amorphous Mg 90 Ca 10 and Mg 70 Zn 30 (at%) alloys exhibited high specific tensile strength of more than 2.5 X 10 5 Nm/kg and good bending ductility. Solid solubility extension was observed in Mg-Ca, Mg-Li and Mg-Zn RS alloys. The solid solution had a ductile nature for the Mg-Al and Mg-Zn RS alloys, while brittle for the Mg-Ca and Mg-Li RS alloys. The Mg-Ca and Mg-Zn RS alloys exhibited an abrup increase in hardness by small addition of the alloying elements. The Mg 94 Al 6 , Mg 90 Al 10 , Mg 98 Ca 2 and Mg 98 Zn 2 RS alloys exhibited both high hardness and good bending ductility after annealing. It is expected that new magnesium RS alloys will be developed hereafter on the basis of these data.

Influence of Ni, Cu, Zn and Al Additions on Glass-Forming Ability and Mechanical Properties of Mg-Y-Mm (Mm=Mischmetal) Alloys

Influence of Ni, Cu, Zn and Al additions on the formation of an amorphous phase in rapidly solidified Mg-Y-Mm alloys, their mechanical properties and thermal stability were the subjects of study in the present paper. The structure of Mg-Y-Mm-(Ni, Cu, Zn or Al) alloys prepared by melt spinning technique has been studied using X-ray diffraction in as-solidified and heat treated state. Their mechanical strength has been examined by using tensile test. The studies showed that quaternary alloys with high mechanical strength and good bending ductility can be produced in Mg-Y-Mm-Ni system. Thermal stability of the amorphous phase and its crystallization in the high-strength Mg-Y-Mm-Ni alloys have been studied using differential scanning calorimetry under continuos heating, Phase composition in fully crystalline state was also determined. Formation of a supercooled liquid and structure relaxation processes precede crystallization of the amorphous phase.

Nanocrystal composites in Zr–Nb–Cu–Al metallic glasses

Adding Nb to Zr–Cu–Al amorphous alloys induces the primary transformation occurring on heating. Nanocrystalline-amorphous composites were produced by annealing Zr 70− y Nb x Cu 30− x Al y ( X=5–7.5 and Y=8–12 at.%) metallic glasses. Their structures, after completing the primary transformation by annealing, were found to consist of fine crystals with a scale less than 15 nm dispersed homogeneously in an amorphous matrix. The nanostructured alloys show increased tensile strength and hardness with good bending ductility at a volume fraction of nanoparticles less than 50%. We suggest that the stronger attractive interaction between Zr–Al is the reason of the presence of the quenched-in embryos in as-solidified samples, and the quenched-in embryos therefore provide nucleation sites for nanocrystal formation.

Bulk amorphous FC20 (Fe–C–Si) alloys with small amounts of B and their crystallized structure and mechanical properties

The addition of a small amount (0.4 mass%) of B to a commercial FC20 cast iron was found to cause the formation of an amorphous phase in melt-spun ribbon and cast cylinders with a diameter of up to 0.5 mm. The structure of a melt-spun B-free FC20 alloy consisted of α-Fe, γ-Fe and Fe 3C. The effectiveness of additional B is presumably due to the generation of attractive bonding nature among the constituent elements. The amorphous alloy ribbon exhibits a high tensile strength of 3480 MPa and good bending ductility. The annealing causes the formation of an amorphous phase containing α-Fe particles with a size of about 30 nm. The mixed phase alloy exhibits an improved tensile strength of 3800 MPa without detriment to good ductility. With further increasing temperature, the mixed amorphous and α-Fe structure changes to α-Fe+Fe 3C+graphite through the metastable structure of α-Fe+Fe 3C. The structure after annealing for 900 s at 1200 K has fine grain sizes of about 0.5 μm for α-Fe, 0.3 μm for Fe 3C and 1 μm for graphite. The graphite-containing alloy exhibits high tensile strength of 1200–2000 MPa and large elongation of 5–13%. The high tensile strength and good ductility were also obtained for the 0.5 mm cylinder annealed at 1200 K. The good mechanical properties are due to the combination of fine subdivision of crack initiation sites by the homogeneous dispersion of small graphite particles and the dispersion strengthening of Fe 3C particles against the deformation of the α-Fe phase. The synthesis of the finely mixed α-Fe+Fe 3C+graphite alloys having good mechanical properties by crystallization of the new amorphous alloy in the melt-spun ribbon and cast cylinder forms is encouraging for the future development of a new Fe-based high-strength and high-ductility material.

Al-Ti-Cr系L1<SUB>2</SUB>型規則構造合金の材料特性に及ぼすV添加の影響

To investigate the effects of vanadium addition on the formation and material properties of the L12-type intermetallic compounds in the Al-Ti-Cr system, button ingots of Al-25Ti-5Cr-4V and Al-xTi-yCr-3V(x=25, 27, 29, y=6, 8, 10, 12, 14) alloys were prepared by arc-melting. The L12-type phase is formed in the (Al, Cr)3Ti-base alloys containing vanadium content up to 4 mol%. The vanadium atom, as well as chromium atom, substantially occupies the Al-site of the L12 structure. The Vickers hardness increases slightly by the addition of vanadium, and is nearly independent on the Cr+V contents, although the higher titanium alloys have larger hardeness. The bend ductility at ambient temperature is not improved by the addition of vanadium. The best ductility is about 0.5% (plastic bend strain) for the Al-25Ti-12Cr-3V alloy. Serrations in the compressive stress-strain curve are observed at 673 and 873 K. The high temperature yielding phenomenon is also observed at 1473 K. This softening behavior is thought to be caused by dynamic recrystallization. The compressive yield strength (0.2% offset) gradually decreases from around 300 MPa at ambient temperature to about 190 MPa at 1300 K, and then decreases rapidly. From tests performed at strain rate varying from 1×10−4 to 2×10−2 s−1, the data reveal that the compressive strength is independent of strain rate at 1173 and 1273 K; although at 1373 and 1473 K strain rate dependency is observed. Thus the L12-type Al-25Ti-5Cr-4V alloy retains a high temperature strength level of about 200 MPa at 1173 K. The L12-type alloys in the Al-Ti-(Cr+V) system have a smaller linear expansion coefficient and an excellent oxidation resistance as well as the L12 Al-Ti-Cr alloys without vanadium.

Production of Zr-based Amorphous Wires by Rotating Disk Casting Method

AbstractContinuous amorphous wires with high strength and good ductility have been produced for the Zr55Al10Ni5Cu30and Zr55Ti5Al10Ni10Cu20alloys by a rotating disk casting technique. The rotating disk, which is made of copper, has a semicircular groove on its upside surface. The amorphous wires have a nearly circular cross-section, smooth peripheral surfaces and diameters in the range from 0.5 to 1.5mm. The amorphous alloy wires have good bending ductility. The maximum tensile strength, μf, is 1600 MPa for Zr55Al10Ni5Cu30 amorphous wire and 1900 MPa for Zr55Ti5Al10Ni10Cu20 amorphous wire, respectively. The success of forming amorphous alloy wires in a continuously long form by the present casting method is important for the further extension of application fields of amorphous alloys.

New Fe-based amorphous alloys with large magnetostriction and wide supercooled liquid region before crystallization

A glass transition, followed by a supercooled liquid region was found in wide composition ranges of 0–65 at % Co and 1.5–7 at % Ln in Fe80−x−yCoxLnyB20 (Ln=Nd, Sm, Tb, or Dy) amorphous alloys. The supercooled liquid region (ΔTx) shows the largest value of 41 K for the Fe47Co30Sm3B20 alloy. An internal equilibrium state leading to the disappearance of the previous thermal history was achieved within a temperature interval of 15 K. The Fe–Co–Ln–B amorphous alloys exhibit soft ferromagnetism with saturated magnetization (Bs) of 0.84–1.66 T and coercivity (Hc) of 5.0–36 A/m. A high magnetostriction (λs) exceeding 40×10−6 was also observed in the composition range of 0–10 at % Co and 1.5–3 at % Ln (Ln=Sm, Tb, or Dy). The highest λs reaches 58×10−6 for Fe68.5Co10Ln1.5B20 (Ln=Sm or Tb), which is higher than the highest value (44×10−6) for previously reported amorphous alloys. All the Fe68.5Co10Ln1.5B20 amorphous alloys have good bending ductility. The tensile strength, Vickers hardness and Young’s modulus of the Fe68.5Co10Sm1.5B20 alloy are 3220 MPa, 990 and 76.5 GPa, respectively. The combination of high λs, high Bs, low Hc, large ΔTx, good ductility and high mechanical strength is promising a new type of ferromagnetic bulk amorphous alloy.

Thermal and Magnetic Properties of Fe–Co–Ln–B (Ln=Nd, Sm, Tb or Dy) Amorphous Alloys with High Magnetostriction

A supercooled liquid region before crystallization was found in wide composition ranges of 0 to 65 at%Co and 1.5 to 7 at%Ln in Fe 90-x-y Co x Ln y B 20 (Ln=Nd, Sm, Tb or Dy) amorphous alloys. The supercooled liquid region shows the largest value of 41 K for the Fe 47 Co 30 Sm 3 B 20 alloy. Besides, an internal equilibrium state leading to the disappearance of the previous thermal history is achieved within a temperature interval of 15 K. Furthermore, the Fe-Co-Ln-B amorphous alloys exhibit soft ferromagnetism with saturated magnetization (B s ) of 0.84 to 1.66 T and coercivity (H c ) of 5.0 to 36 A/m at room temperature. In addition, a high magnetostriction (λ s ) exceeding 40 × 10 -6 was observed in the composition range of 0 to 10 at%Co and 1.5 to 3 at%Ln (Ln=Sm, Tb or Dy) while the highest λ s reaches 58 × 10 -6 for Fe 68.5 Co 10 Ln 1.5 B 20 (Ln=Sm or Tb), which is higher than the highest value (44 ×10 -6 ) for previously reported amorphous alloys. All the Fe 68.5 Co 10 Ln 1.5 B 20 amorphous alloys have good bending ductility. The tensile fracture strength, Vickers hardness and Young's modulus of the Fe 68.5 Co 10 Sm 1.5 B 20 amorphous alloy are 3220 MPa, 990 and 76.5 GPa, respectively. The good combination of high λ s , high B s , low H c , large ΔT x , good ductility and high mechanical strength is a promising new type of ferromagnetic bulk amorphous alloy.

Effect of Vanadium on Residual Strain in L1<SUB>2</SUB>-Type (AlMn)<SUB>3</SUB>Ti(V) Alloy Powders and Bend Ductility of Pre-Milling Alloys

To examine the effect of vanadium addition on the ductility of the L12-type (AlMn) 3 Ti phase alloys, the residual strains in powder specimens of the L1 2 -type (AlMn) 3 Ti phase alloys were examined with changing the amount of vanadium up to 7 mol% by X-ray diffraction analysis. Some of the alloys were also examined by three-point bend testing and Laser optical microscopy. The vanadium addition up to 6 mol% increased the residual strain and decreased the porosity in the microstructure of alloys. The bending strain also increased with addition of vanadium up to 6 mol%, i.e. room-temperature ductility of the L1 2 -type (AlMn) 3 Ti phase alloys was improved by addition of vanadium. The relation between the residual strain in powder specimens and the bending strain in the bulk specimens exhibited a linear and positive correlation, and suggested the residual strain will be able to use for ductility evaluation of the L1 2 -type (AlMn)3Ti phase alloys.

Synthesis of TiAl–(TiB<SUB>2</SUB>+Ti<SUB>2</SUB>AlN) Composites by HIP Reactive Sintering

Intermetallic compound TiAl-base composites have been prepared by the hot isostatic pressing (HIP) reactive sintering technique. These composites have been synthesized from a powder mixture of titanium, aluminum and boron nitride, and contain Ti 2 AlN and TiB 2 strengthening particles. Nearly spherical particles of Ti 3 Al and Ti 2 AlN of about 20 μm in diameter have been embedded in the TiAl phase. The composite has been found with a dual phase matrix structure. The Ti 2 AlN phase is composed of about 300-500 nm grains and includes dispersion of nano scaled TiB 2 particles (about 50-100 nm). Both compression tests and hardness measurements have revealed that this composite material attains higher strength as compared with non-reinforced TiAl. The insufficient bending ductility, however, hinders its bending fracture strength at ambient temperature.

Bulk Amorphous FC20 (Fe–C–Si) Cast Iron with Small Addition of B

The addition of a small amount (1.5 at%) of B to a commercial FC20 alloy was found to cause the formation of an amorphous phase in a melt-spun ribbon as well as in a cast cylindrical ingot with a diameter of 0.5 mm. The melt-spun B-free FC20 alloy is composed of α-Fe, γ-Fe and Fe 3 C. The additional B has great effectiveness on the increase in the glass-forming ability presumably because of the generation of attractive bonding nature among the constituent elements. The melt-spun amorphous alloy exhibits a high tensile strength of 3480 MPa and good bending ductility. The crystallization takes place by the following process; amorphous (Am)→Am'+α-Fe→Am+α-Fe+Fe 3 C→α-Fe+Fe 3 C →α-Fe+Fe 3 C+graphite. The final structure obtained by annealing for 900 s at 1200 K has fine grain sizes of about 0.5 μm for α-Fe, 0.3 μm for Fe 3 C and 1 μm for graphite, The graphite-containing alloy ribbon also exhibits high tensile strength of 1200 to 2000 MPa and large elongation of 5 to 13% which exceed largely those (200 to 300 MPa and approximately zero %) for FC20 cast iron, depending on annealing condition. The cast amorphous cylinder with a diameter of 0.5 mm annealed for 3.6 ks at 1200 K also exhibits high tensile strength of 1530 MPa, large elongation of 9% and good bending ductility. The good mechanical properties are presumably due to the combination of fine subdivision of crack initiation sites caused by the homogeneous dispersion of small graphite particles and the dispersion strengthening of fine Fe 3 C particles against the deformation of α-Fe phase. The synthesis of the mixed bulk alloy of α-Fe, Fe 3 C and graphite phases having good mechanical properties by crystallization of the new amorphous alloy is promising for the future development of the FC20 type alloy as a new type of high-strength and high-ductility material.

New Amorphous Alloys in Al–Ti Binary System

An amorphous phase was found to be formed in coexistence with the fcc-Al phase for Al 92 Ti 8 and with fccAl+Al 2 Ti for Al 90 Ti 10 by melt spinning with a circumferential velocity (V f ) of 40 m/s. The further increase in V f to 50 m/s causes the formation of a mostly single amorphous phase at 10%Ti. The amorphous +fcc-Al and amorphous+fccAl+Al 2 Ti alloys have good bending ductility and exhibit a high tensile fracture strength of 810 to 820 MPa and a high Vickers hardness of 300 to 310. Crystallization of the amorphous phase in the Al 90 Ti 10 alloy takes place by two-stage reactions of Am→icc-Al+Al 2 →fccAl+Al 3 Ti Considering that the as-quenched phase of the Al 95 Ti 5 alloy consists of fcc-Al + Al 3 Ti phases, it is interpreted that the formation of the amorphous phase in coexistence with the fcc-Al phase is due to the enrichment of Ti content in the remaining supercooled liquid to a critical solute concentration for glass formation and to the suppression of precipitation of Al-Ti compounds from the supercooled liquid with the enriched Ti contents. The enrichment phenomenon of the solute element in the remaining liquid seems to be hereafter utilized as a useful mechanism for the synthesis of an amorphous phase in the low solute concentration alloys where no amorphous phase is formed in the rapidly solidified state.

Formation, Thermal Stability and Mechanical Properties of New Amorphous Al<SUB>89</SUB>Fe<SUB>10</SUB>Zr<SUB>1</SUB> Alloy

A new amorphous alloy with high tensile strength and good bending ductility was fabricated from a melt-spun Al 89 Fe 10 Zr 1 alloy without the lanthanide (Ln) element. The Al content for glass formation is believed to be the highest in the Ln-free Al-based alloys. The as-quenched phase changes to a mixed structure of amorphous and fcc-Al phases with decreasing Fe content to 7-9 at%, and the particle size of the Al phase is 40 nm at 7%Fe, 10 nm at 8%Fe and 5 nm at 9%Fe. The mixed phase alloys also have good bending ductility. The tensile fracture strength (σ f ) is 1050 MPa for the amorphous Al 89 Fe 10 Zr 1 alloy and decreases to 720-1000 MPa for the mixed phase alloys with 7 to 9%Fe concentrations. The amorphous alloy crystallizes by two-stage reactions of Am→Am+Al→Al+Al 3 Zr+Al 13 Fe 4 and the onset temperature of each exothermic reaction is 460 and 650 K. The σ f of the amorphous alloy increases to 1220 MPa without detriment to good ductile nature by the precipitation of about 20 vol% Al phase. The achievement of high σ f combined with good bending ductility in the Ln-free Al-Fe-Zr alloys with the high Al concentration of about 90% is important as a new basic alloy system to produce a high-strength Al-based alloy with low specific weight and inexpensiveness.

Production and properties of amorphous alloy wires in Fe-B base system by a melt extraction method

The application of a melt extraction method to Fe-B based alloys was found to cause the formation of continuous amorphous alloy wires with good bending ductility. The wire diameter is in the range of 20–50 μm for the Fe 80B 20 and Fe 80B 14C 6 alloys and 20–60 μn for the Fe 80B 10P 10 alloy. The wires have a nearly real circular cross-section and good mechanical and magnetic properties. The good formability into the wire shape for the Fe-B based alloys without a high degree of shape stability in the molten state allows us to expect that the present process can develop as an alternative method to produce amorphous alloy wires in various alloy systems in which an amorphous wire has not yet been prepared.

Microstructure and Mechanical Properties of Ternary L1<SUB>2</SUB> Intermetallic Compound in Al–Ti–Cr System

Sintering of elemental powders was carried out to form ternary L1 2 intermetallic compounds in Al-Ti-Cr alloys. The L1 2 phase field and equilibrium phases surrounding the L1 2 phase at 1423 K have been established. Besides the L1 2 phase, the pertinent second phase fields have been also estimated; TiAl, TiAl 2 , Ti 2 Al 5 , Al 3 Ti, Al 17 Cr 9 , AlCr 2 , and TiAlCr phase fields. The vertical section of the Al-25 mol%Ti-Cr alloys has been experimentally determined, and the presence of the L1 2 + Liquid phase field in the present composition and temperature ranges was confirmed. Button ingots of some ternary L1 2 compounds in the Al-Ti-Cr alloys were prepared by arc-melting to investigate their microstructure (especially second phases and porosity), microhardness, and bend ductility. In general, homogenization of as arc-melted alloys substantially reduced the amount of second phases but introduced extensive porosity. Therefore, the formation of porosity is closely associated with the second phase solutionized during homogenization treatment. However, no residual porosity was observed in higher Cr alloys. The porosity after homogenization was observed when Al 17 Cr 9 phase is formed and not when the TiAlCr or AlCr 2 phase is formed. The ternary L1 2 compounds in the Al-Ti-Cr alloys had some bend ductility at ambient temperature, which can be increased to about 0.9% (plastic bend strain) by increasing the Cr content when porosity is reduced.

Improvement of Mechanical Properties by Precipitation of Nanoscale Compound Particles in Zr–Cu–Pd–Al Amorphous Alloys

The replacement of Cu by 10 at%Pd for an amorphous Zr 60 Cu 30 Al 10 alloy was found to change the crystallization process from the single stage of amorphous (Am)→Zr 2 Cu+Zr 2 Al to the two stages of Am→Am'+Zr 2 (Cu, Pd) →Zr 2 (Cu, Pd)+Zr 3 (Al, Pd) 2 in the maintenance of the wide supercooled liquid region before crystallization. After the melt-spun amorphous alloys were annealed for 1.2 ks at 726 K and the volume fraction (V f ) of compound reached as large as 75%, the particle size and interparticle spacing of the compound particles in the amorphous matrix were 10 and 1.5 nm, respectively. The residual amorphous phase enabled the maintenance of the nanoscale compound particles. The nanoscale mixed phase alloy remains good bending ductility even at V f =75% and exhibits high tensile strength (σ f ) of 1910 MPa which is higher than that (1640 MPa) for the amorphous single phase. The increase of the thermal stability of the remaining amorphous phase is presumably due to the generation of the strong bonding pair mainly among Zr, Pd and Al. The good ductility of the mixed phase alloy is due to the suppression of embrittlement for the remaining amorphous phase because the partial crystallization is made in the supercooled liquid region. The first achievement of high σ f and good ductility for the mixed phase alloy with nanoscale Zr 2 (Cu, Pd) phase surrounded by the amorphous phase is important for future progress of high-strength nanocrystalline bulk alloys.

Microstructure and thermal analysis of amorphous Al 87RE 8Ni 5 and Al 92RE 4Ni 4 alloys

Ternary Al-Ni rare earth (RE) amorphous alloys, Al 87RE 8Ni 5 and Al 92RE 4Ni 4 (at%), with superior bending ductility, were produced by melt-spinning in air. For the ribbons, 50–60 μm thick, the Al 87RE 8Ni 5 alloy was found to be amorphous with no trace of crystallinity, whereas the Al 92RE 4Ni 4 alloy ribbon was amorphous on the wheel side, amorphous containing finely dispersed (α-Al particles (about 5 nm in diameter) in the ribbon core, and material with an (α-Al micrograin structure, with grain size of 15–20 nm, in the free side. Amorphous Al 87RE 8Ni 5 and Al 92RE 4Ni 4 alloys all possess a very wide temperature span for the supercooled liquid, ( ΔT x = 53 and 83 K respectively, and a distinct glass forming ability with T g T m = 0.56 and 0.59 respectively.