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Ti33.33Zr33.33Hf13.33Ni20 and Zr30Hf30Ni15Cu10Ti15 alloys were investigated for their possibility to be formed into a high-entropy alloy (HEA) with a quasicrystalline (QC) structure that contains an icosahedral- (I-) phase. The melt-spun alloys quenched at a circumference speed of 39 m/s were formed into an amorphous single phase. The amorphous alloys annealed up to a temperature between the first and second crystallization temperatures exhibited mixed phases of I- and remaining amorphous phases. Observation of the Zr30Hf30Ni15Cu10Ti15 amorphous alloy heated up to 745 K with transmission electron microscope revealed the presence of precipitates with diameters ranging 10–20 nm. Nano-beam diffraction demonstrated that the precipitates were identified to be the I-phase with the five-, three- and two-fold symmetries. The Ti33.33Zr33.33Hf13.33Ni20 and Zr30Hf30Ni15Cu10Ti15 alloys were not formed into a single quasicrystalline phase as HEAs, but the discussions of the current and early experimental data led to provide the way to approach high-entropy quasicrystalline alloys (HE-QCs).

A senary ScYLaTiZrHf alloy was investigated for its ability to form a solid solution with an hcp structure, also known as a high-entropy alloy (HEA). X-ray diffraction analysis of the ScYLaTiZrHf alloy produced by arc-melting method confirmed this hcp structure. The microstructure of the ScYLaTiZrHf was composed of dual phases that were enriched in (Y, La) or (Ti, Zr, Hf), with Sc distributed evenly across both phases. The positive mixing enthalpy of 11.4 kJ mol−1 derived from Miedema's model, and the immiscible tendencies of its constituent binary phase diagrams help to explain the presence of dual phases in the ScYLaTiZrHf alloy. When formed into dual hcp solid solutions, the ScYLaTiZrHf alloy can be more accurately described as a multi-principal-element alloy (MPEA) rather than as a HEA, since the ScYLaTiZrHf alloy is a solid solution that is enthalpy-driven instead of entropy driven. The results also disclosed another procedure to stabilize solid solutions excepting for high-entropy scheme.

Pettifor map for binary compounds with 1:1 stoichiometry was utilized as an alloy design for high-entropy alloys (HEAs) with exact or near equi-atomicity in multicomponent systems. Experiments started with selecting GuGd binary compound with CsCl structure from Pettifor map, followed by its extensions by selecting the binary compounds with the same CsCl structure to CuDyGdTbY equi-atomic quinary alloy and to Cu4GdTbDyY and Ag4GdTbDyY quinary alloys and Cu2Ag2GdTbDyY senary alloy in sequence. X-ray diffraction revealed that CuDyGdTbY alloy was formed into a HEA with mixture of bcc, fcc and hcp structures, whereas the Cu2Ag2GdTbDyY HEA was a single CsCl phase. The results suggest a potential of Pettifor map for the development of HEAs by utilizing its information of crystallographic structures. The further analysis was performed for composition diagrams of multicomponent systems corresponding to simplices in a high dimensional space. The present results revealed that a strategy of equi-mole of compounds instead of conventional equi-atomicity also works for the development of HEAs.

High-entropy alloys (HEAs) with an atomic arrangement of a hexagonal close-packed (hcp) structure were found in YGdTbDyLu and GdTbDyTmLu alloys as a nearly single hcp phase. The equi-atomic alloy design for HEAs assisted by binary phase diagrams started with selecting constituent elements with the hcp structure at room temperature by permitting allotropic transformation at a high temperature. The binary phase diagrams comprising the elements thus selected were carefully examined for the characteristics of miscibility in both liquid and solid phases as well as in both solids due to allotropic transformation. The miscibility in interest was considerably narrow enough to prevent segregation from taking place during casting around the equi-atomic composition. The alloy design eventually gave candidates of quinary equi-atomic alloys comprising heavy lanthanides principally. The XRD analysis revealed that YGdTbDyLu and GdTbDyTmLu alloys thus designed are formed into the hcp structure in a nearly single phase. It was found that these YGdTbDyLu and GdTbDyTmLu HEAs with an hcp structure have delta parameter (δ) values of 1.4 and 1.6, respectively, and mixing enthalpy (ΔH mix) = 0 kJ/mol for both alloys. These alloys were consistently plotted in zone S for disordered HEAs in a δ-ΔH mix diagram reported by Zhang et al. (Adv Eng Mater 10:534, 2008). The value of valence electron concentration of the alloys was evaluated to be 3 as the first report for HEAs with an hcp structure. The finding of HEAs with the hcp structure is significant in that HEAs have been extended to covering all three simple metallic crystalline structures ultimately followed by the body- and face-centered cubic (bcc and fcc) phases and to all four simple solid solutions that contain the glassy phase from high-entropy bulk metallic glasses.

The values of mixing enthalpy (¦Hmix) and Delta parameter (¤) were calculated with 73 elements from Miedema’s model for multicomponent equi-atomic alloys to investigate the possibilities of the alloys to be formed into high-entropy (H-E) alloys or high-entropy bulk metallic glasses (HE-BMGs). The equi-atomic alloys from about 15 million (73C5) quinary to 621 billion (73C10) decimal systems were evaluated by referring to a ¦Hmix­¤ diagram for zones S and B’s for H-E alloys with disordered solid solutions and BMGs, respectively, reported by Zhang et al. The results revealed that the number of quinary equi-atomic alloys plotted in zone S is 28405 (30.19% in 73C5), whereas those in zones B1 and B2 for conventional and Cuand Mg-based BMGs, respectively, were 1036385 and 21518 (36.90 and 30.14%), respectively. This kind of statistical approach using ¦Hmix­¤ diagram will lead to finding out unprecedented H-E alloys and HE-BMGs. [doi:10.2320/matertrans.M2013352]

Fatigue tests were carried out on ultra-high strength Co- and Fe-based bulk metallic glasses (BMGs), and the fatigue results were investigated together with the ones which had already been obtained from the fatigue tests on the super-high strength Ni-based BMG and the high strength Ti- and Cu-based BMGs. The test alloy rods with a diameter of 2 mm were prepared in [(Co 0.6 Fe 0.4 ) 0.75 B 0.2 Si 0.05 ] 96 Nb 4 , (Fe 0.5 Co 0.5 ) 72 B 20 Si 4 Nb 4 , Ti 41.5 Zr 2.5 Hf 5 Cu 42.5 Ni 7.5 Si 1 , Ni 60 Zr 20 Nb 15 Al 5 and Cu 60 Zr 30 Ti 10 at% systems by the copper mold casting method. The test specimens were machined to hourglass shape type with a minimum diameter of 0.9 mm. The specimens were tested at a stress ratio of 0.1 and a frequency of 10 Hz. The fatigue limits in the Co- and Fe-based BMGs exceeded 2 GPa, and those in the Ni- and Ti-based BMG surpassed about 1.5 GPa. Fatigue ratios in all BMGs were found to be about 0.5. Exceptionally, only the Ti-based BMG showed the high ratio, which may indicate the possibility that the BMG does not cause the fatigue phenomenon. In front of the fatigue crack initiation sites, fracture surfaces showed a radial ridges and valleys morphology as well as a striation like pattern. Unstable fracture surfaces consisted of facets with vein patterns. As the facet and vein pattern sizes increase, the strength and fatigue limit decreased, whereas the fracture toughness increased. Fracture surfaces in front of the fatigue cracks in strong BMGs showed the clear elastic wave traces.

The influence of the substrate temperature on the structure, the pore distribution, and the adhesion strength of Fe-10Cr-based amorphous coating films has been examined. The amorphous coating films have been produced by a thermal spraying technique using our developed cylindrical nozzle on SS400 substrates. The splat morphology of the sprayed particles changed drastically from an irregular splash shape to a disk shape at a transition temperature of about 325°C. When the substrate temperature increased to the transition temperature region, between 325 and 350°C, the porosity in the boundary regions between the sprayed coating films and the substrates drastically decreased to about 6%, which may be due to the drastic increase in the wettability of the sprayed particles accompanied with the change of morphology from the splashed shape to the disk shape. When the substrate temperature increased from the transition temperature of 325°C up to 400°C, the porosity decreased gradually, and the volume fraction of the amorphous phase increased with increasing substrate temperature, resulting in an increase in the adhesion strength up to about 15MPa. [doi:10.2320/matertrans.M2011261]

In this paper, ion-implantation technique was applied to improve corrosion resistance of a newly developed La-based bulk metallic glass with poor corrosion resistance. It is found that the alloys after ion implantation with doses ranging 6 × 1016–1 × 1017 Nb/cm2 have a remarkable enhancement of corrosion resistance in chloride containing environments and acid solution with respect to the alloy without the surface treatment while the implanted alloys still have high glass forming ability. The improvement of corrosion resistance for the implanted alloys is attributed to the high passivating ability of the Nb-containing surface layer. These results obtained here clearly demonstrate that the ion-implantation technique could be a useful method to improve the corrosion resistance of bulk metallic glasses without losing glass forming ability of alloys.

A glassy Fe-base alloy plate with a composition of Fe 36 Co 36 B 20 Si 4 Nb 4 (at.%) was prepared by a twin-roller continuous casting method. The alloy plate had a width of 70 mm, a thickness of 0.5 mm and a length of 150 mm. The cast plate contained small crystalline grains in the glassy matrix. These crystalline grains were identified as an α-Fe ( cI 2) phase. Thermal characteristics of the plate are almost consistent with those of the melt-spun ribbon, while the exothermic heat of crystallization for the cast plate is about 5% smaller than that for the ribbon. The coercive force ( H c ) and maximum permeability ( μ m ) of the Fe-base alloy in a ring form of 10 mm in outer diameter, 5 mm in inner diameter and 0.6 mm in thickness made by mechanical machining from the cast plate are 2.1 A/m and 40,000, respectively, for the as-cast one, and 1.6 A/m and 170,000, respectively, for the annealed one at 723 K for 1800 s under rotation magnetic field of 80 kA/m. It can be thus said that the cast plate has good soft magnetic properties. The possibility of forming a glassy alloy plate by twin-roller continuous casting is confirmed and the Fe-base glassy alloy plate produced by the developed continuous process will be applicable for magnetic parts.

An in situ formed (Cu 0.6 Hf 0.25 Ti 0.15 )9oNbio (number indicate at.%) bulk metallic glass (BMG) composite was prepared by copper mold casting. The ductile Nb-rich crystalline phase with a dendritic structure disperses homogeneously in the glassy matrix. The (Cu 0.6 Hf 0.25 Ti 0.15 )9oNbio composite alloy exhibits much higher corrosion resistance in IN HCl and 3 mass% NaCl solutions than the Nb-free alloy. The addition of Nb is favorable for the alloys to form a Hf-, Ti- and Nb-enriched highly protective surface film with higher chemical stability in HCl and NaCl solutions. Young's modulus, compressive fracture strength and compressive plastic strain of the (Cu 0.6 Hf 0.25 Ti 0.15 )9oNbio BMG composite are 106 GPa, 2625 MPa and 12.5%, respectively. The increase in compressive strain-to-failure is due to the ductile dendrites restricting shear band propagation, promoting the generation of multiple shear bands.

Mg-8Zn-4Al-xY base alloys containing an icosahedral quasicrystal phase (i-phase) as a main strengthening phase were prepared by casting into a copper mould at moderate cooling rates. The Y addition was effective for decreasing the size of i-phase and the more homogeneousness of its dispersed state. The mechanical properties at room temperature were much superior to those of AZ91 alloy. The creep tests indicated a promising high temperature creep resistance of the quasicrystal-reinforced Mg-Zn-Al-Y cast alloy. The dislocation characteristic in crept specimens which containing i-phase and no i-phase was analyzed and strengthening mechanism was discussed.

A new type of Mg–Zn–Cu–Gd-based alloy strengthened by quasicrystal and Laves phase was developed. This alloy exhibits much better creep properties compared to AE42(Mg–4 wt% Al–2 wt% rare-earth) alloy, which is the benchmark creep-resistant magnesium die-casting alloy under the compressive creep condition of 180 °C and80 MPa. The new alloy also exhibits high room-temperature mechanical properties close to that of AZ91 alloy. The good mechanical properties are attributed to the special microstructure; the thermally stable icosahedral quasicrystals phase (i-phase) and Laves phase distributed along the grain boundary as a hard skeleton, and some fine β′1 precipitates distributed homogenously on the matrix. The dislocation morphology after the creep test was studied, and the strengthening mechanism was proposed.

The structural relaxation and glass-forming ability (GFA) of Mg–Cu–Gd-based glassy alloys and the effect of Ni addition on the glass-forming ability, structural relaxation and mechanical properties were studied by thermal analysis, X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The medium-range order (MRO) zones of about 1–2 nm size were observed in the Mg 65 Cu 25 Gd 10 glassy alloy after structural relaxation caused by annealing for 180 s at 305 K. The structural relaxation resistance increased with decreasing Cu content, although the GFA also decreased in Mg–Cu–Gd-based alloys. Appropriate substitution of Cu by Ni in Mg 75 Cu 15 Gd 10 -based alloy not only improved the glass-forming ability and mechanical properties, but also increased the stability against structural relaxation.

The structure and mechanical properties of Mg–Zn–Al–Y base cast alloys containing an icosahedral quasicrystal phase (i-phase) as a main strengthening phase were investigated. Mg–8Zn–4Al–xY base bulk alloys containing the i-phase were prepared by casting into a copper mold at moderate cooling rates. The Y addition was effective for decreasing the size of the i-phase and the increasing the homogeneity of its dispersed state. The mechanical properties examined by compression tests at room temperature were much superior to those of a conventional AZ91 Mg alloy. The creep tests at elevated temperatures indicated a promising high temperature creep resistance of the quasicrystal-reinforced Mg–Zn–Al–Y cast alloy. The strengthening mechanism was also discussed.

By use of excellent properties of bulk metallic glasses, some industrial products were practically prepared and their performances were investigated. Ni-based BMG microgear prepared by injection casting exhibits nano-imprintability against the surface roughness of mold. Linear actuator constructed by a set of Fe-based BMG yokes generates relatively large driving force due to the Lorentz force. The newly developed alloy with a nominal atomic composition of Ti52Cu23Ni11Mo7Fe7 exhibits high yield strength of 1250 MPa, high fracture strength of 2740 MPa and large plastic elongation of over 20%. These results for the industrial products made of BMGs are promising for future developments as industrial materials with high performance.

Novel long-period hexagonal structures with six and fourteen layered atomic configurations were formed in melt-spun Mg97Ln2Zn1 (Ln=Y, Gd and Sm) ternary alloys annealed at 573 K for 1.2-3.6 ks and in an as-spun Mg97Y2Zn1 alloy, respectively. The Mg-based alloys containing La or Ce as the Ln element have a mixed structure of hcp Mg and compound phases and no long-period hexagonal structure is formed in the as-spun and annealed states. There is a clear formation tendency of the novel long-period structure to increase with a decrease in the precipitation tendency of the intermetallic compound, an increase in the atomic size ratio of Ln/Mg and an enhancement of the formation tendency of Mg-based reinforced solid solution. The formation of the novel long-period structure is interpreted to result from the necessity of relaxation of strains caused by the reinforced solid solution of Ln and Zn elements into the Mg phase. In addition, the enrichment of Y and Zn elements was observed at the misfit sites of the atomic array in the fourteen layered hexagonal structure of the as-spun Mg97Y2Zn1 alloy. The atomic level segregation of Y and Zn elements is also thought to be the origin for the high stability of the long-period structure. The two types of long-period hexagonal structures found in the Mg-Ln-Zn alloys are important as a new mechanism for future development of high-strength Mgbased alloy.

New bulk glassy alloys were formed in the Ca-Mg-Cu system by the copper mold casting method. The maximum rod diameter (d max ) for the formation of a glassy phase was 2mm for Ca 67 Mg 19 Cu 14 and above 4 mm for Ca 57 Mg 19 Cu 24 . The glass transition temperature (Tg), crystallization temperature (T x ), supercooled liquid region (ΔT x = T x -T g ) and reduced glass transition temperature (T g /T m ) are 387 K, 407 K, 20 K and 0.60, respectively, for the former alloy and 404 K, 440 K, 36 K and 0.64, respectively, for the latter alloy. There is a tendency for d max to increase with increasing ΔT x and T g /T m . Young's modulus (E) and compressive fracture strength are 38 GPa and 545 MPa, respectively, for the Ca 57 Mg 19 Cu 24 alloy rod with a diameter of 2 mm. The success of synthesizing bulk glassy alloys in the simple metal (Ca) base system makes it important as a basic alloy system for examining fundamental chemical and physical properties of bulk glassy alloys.

Calcium-based bulk glassy alloys in Ca-Mg-Ag and Ca-Mg-Ag-Cu systems were produced by a metallic mold casting method. The maximum rod diameter (d max ) for the formation of a glassy phase was 4 mm for Ca 60 Mg 20 Ag 20 and 7 mm for Ca 60 Mg 20 Ag 10 Cu 10 . The glass transition temperature (Tg), crystallization temperature (Tx), temperature interval of supercooled liquid region (ΔT x = T x - T g ) and melting temperature (T m ) were 401 K, 435 K, 35 K and 654 K, respectively, for the former alloy and 398 K, 428 K, 30 K and 624 K, respectively, for the latter alloy. The simultaneous addition of Ag and Cu in the Ca-Mg-(Ag, Cu) system causes a steep decrease in T m and an increase in the reduced glass transition temperature (T g /T m ), leading to an increase in the glass-forming ability.

A magnesium (Mg) solid solution with a novel long periodic hexagonal structure was formed for a Mg97Zn1Y2 (at%) alloy in a rod form prepared by extrusion of atomized powders at 573 K as well as in a melt-spun ribbon form. The novel structure of the rod alloy had an ABACAB-type six layered packing with lattice parameters of a = 0.322 nm and c = 3 × 0.521 nm. The Mg phase in the extruded rod alloy had fine grain sizes of 100 to 150 nm and included cubic Mg24Y5 particles with a size of about 10 nm at volume fractions below 10%. The density (ρ) was 1.84Mg/m 3 . The tensile yield strength (σy) and elongation of the rod alloy were 610 MPa and 5%, respectively, and the specific strength defined by the ratio of σy to ρ was 330 MPa/(Mg/m 3 ), being the highest among all metallic alloys. The σy is 2.7 to 8 times higher than those for conventional high-strength Mg-based alloys. The excellent mechanical properties are due to the combination of fine grain size, new long periodic hexagonal solid solution, homogeneous dispersion of fine Mg24Y5 particles inside the nano-grains and the absence of the second precipitates along the grain boundary. The new Mg-based alloy is promising for future uses in many fields.

High-entropy (H-E) alloys, bulk metallic glasses (BMGs) and high-entropy BMGs (HE-BMGs) were statistically analyzed with the help of a database of ternary amorphous alloys. Thermodynamic quantities corresponding to heat of mixing and atomic size differences were calculated as a function of composition of the multicomponent alloys. Actual calculations were performed for configurational entropy (Sconfig.) in defining the H-E alloys and mismatch entropy (Ss) normalized with Boltzmann constant (kB), together with mixing enthalpy (DHmix) based on Miedema’s empirical model and Delta parameter (d) as a corresponding parameter to Ss/kB. The comparison between DHmix–d and DHmix– diagrams for the ternary amorphous alloys revealed Ss/kB ~ (d /22)2. The zones S, S′ and B’s where H-E alloys with disordered solid solutions, ordered alloys and BMGs are plotted in the DHmix–d diagram are correlated with the areas in the DHmix – Ss /kB diagram. The results provide mutual understandings among H-E alloys, BMGs and HE-BMGs.

The application of a melt extraction method to Ti- and Al-based alloys with highly reactive molten states was found to cause the formation of continuous amorphous alloy wires with good bending ductility. The wire diameter is in the range of 40 to 150 μm for Ti 40 Zr 10 Cu 50 and 40 to 100 μm for Al 85 Ni 10 Ce 5 and the difference reflects the difference in the glass-forming ability between both alloys. The glass transition temperature, crystallization temperature and heat of crystallization are 629 K, 691 K and 1.71 kJ/mol, respectively, for the Ti-based wire with the diameter of 100 μm and 530 K, 546 K and 0.37 kJ/mol for the Al-based wire with the diameter of 50 μm. The tensile strength is 2000 MPa for the former wire and 930 MPa for the latter wire. The thermal stability and mechanical strength are nearly the same as those for the melt-spun amorphous ribbons with the thickness of 15 μm. No appreciable concave resulting from the use of the copper wheel with a steep edge is seen in the cross section and the solidification is completed during the flight after extraction. The cooling rate of the Al-based wire with the diameter of 70 μm is estimated to be of the order 6 x 10 4 K/s. Thus, the formation of the amorphous alloy wires with a circular cross section is due to the rapid solidification of the fine supercooled liquid stream in the suppression of heterogeneous nucleation during the high-velocity flight in the argon atmosphere. The combination of the solidification process with high cooling rate and the good formability into the wire shape allows us to expect that the present process develops as an alternative method to produce amorphous alloy wires in various kinds of alloy systems including reactive elements as main components.

Amorphous (Fe, Co)-Si-B ternary and quaternary wires were found to be produced over a wire diameter range of 20 to 80 μm by a melt extraction method using a copper wheel with an edge angle of 60 degrees. The wires without any concaves in the transverse cross section were prepared in the extraction condition where the circumferential velocity of the wheel and the rising velocity of the molten alloy are in the range of 20 to 40 m/s and 0.1 to 4.0 mm/s, respectively. The resulting amorphous wires have good bending ductility in the wire diameter range below 80 μm for the Fe 75 Si 10 B 15 alloy and below 60 μm for the Co 72.5 Si 12.5 B 15 alloy. The thermal stability and mechanical properties except tensile fracture strength (σ f ) for the amorphous wires are nearly the same as those for the melt-spun amorphous ribbons. The σ f is 3800 MPa for the Fe 75 Si 10 B 15 wire and 3600 MPa for the Co 72.5 Si 12.5 B 15 wire, being about 10% higher than those for the corresponding ribbon samples because of the low degree of stress concentration resulting from the good smoothness on the outer surface. The magnetic properties of saturation magnetization, coercivity and effective permeability at 1 kHz for the wires are nearly the same as those for the ribbons. The squareness of the hysteresis B-H loop for the Fe-Si-B amorphous wire is better than that for the same Fe-based ribbon and the sharp output voltage due to the reversion of magnetic flux is also observed for the present Fe 78 Si 10 B 12 amorphous wire. The combined properties of good mechanical properties and unique magnetic properties leading to the generation of the sharp output voltage seem to be promising for the subsequent development of the present fine amorphous wires.

Ti-based alloy powders produced by the high pressure gas atomization technique were found to consist of an amorphous single phase in the particle size range below 32 μm for Ti 50 Zr 10 Cu 40 and below 25 μm for Ti 50 Zr 10 Ni 20 Cu 20 , though the cooling rate of their molten alloys for gas atomization is considerably lower than that for melt spinning. In addition, the TiZrCu amorphous powders exhibit a rather wide supercooled liquid region before crystallization. This is believed to be the first evidence for the appearance of the supercooled liquid region for atomized Ti-based amorphous powders. The significant increase in the glass-forming ability and the wide temperature range of the supercooled liquid region for the TiZrCu ternary alloys are presumably due to the simultaneous satisfaction of the two criteria of the significantly different atomic size ratios among the constituent elements and the difficulty of long-range redistribution of the constituent elements for the growth of crystalline phases.

Cylindrical glassy alloys with diameters up to 12 mm were prepared for-a Mg 65 Y 10 Cu 15 Ag 5 Pd 5 with a high reduced glass transition temperature (T g /T m ) of 0.62 by water quenching the molten alloy in the iron tube. Neither cavities nor voids are seen over the whole inner region and no contrast revealing a crystalline phase is seen over the transverse cross section. The glass transition temperature (T g ), crystallization temperature (T x ), the temperature interval of the supercooled liquid region (ΔT x = T x - T g ) and the melting temperature (T m ) are measured to be 436, 468, 32 and 706 K, respectively, for the Mg 65 Y 10 Cu 15 Ag 5 Pd 5 alloy with a diameter of 12 mm. The simultaneous addition of Ag and Pd to Mg-Y-Cu system causes an increase in the T g /T m , leading to an increase in the glass forming ability. It is thus concluded that the application of the water quenching process with the iron tube to the Mg-based glassy alloys is useful for the formation of the bulk glassy alloys.

Magnesium-based bulk amorphous alloys with a diameter of 7 mm for Mg 65 Y 10 Cu 15 Ag 5 Pd 5 were produced by a metallic mold casting method. The glass transition temperature (T g ), crystallization temperature (T x ), the temperature interval of the supercooled liquid region (ΔT x = T x - Tg) and the melting temperature (T m ) are measured to be 437, 472, 35 and 707 K, respectively, for the Mg 65 Y 10 Cu 15 Ag 5 Pd 5 alloy. The simultaneous addition of Ag and Pd to Mg-Y-Cu system causes a steep decrease in T m and an increase in the reduced glass transition temperature (T g /T m ), leading to an increase in the glass-forming ability. The Mg-Y-Cu-(Ag, Pd) bulk amorphous alloys have a high compressive fracture strength of 770 MPa. The simultaneous addition of Ag and Pd is useful for the improvements of glass-forming ability and fracture strength.

By use of excellent properties of bulk metallic glasses, some industrial products were practically prepared and their performances were investigated. Linear actuator constructed by a set of Fe-based BMG yokes generates large Lorentz force due to the large permeability and saturation magnetization of the BMG. Ni-based BMG microgear prepared by injection casting exhibits nano-imprintability against the surface roughness of mold. The newly developed alloy with a nominal atomic composition of Ti52Cu23Ni11Mo7Fe7 exhibits high yield strength of 1250 MPa, high fracture strength of 2740 MPa and large plastic elongation of over 20 %. These results for the industrial products made of BMGs are promising for future developments as industrial materials with high performance.