CA1121184A - Iron group transition metal-refractory metal-boron glassy alloys - Google Patents

Abstract

INVENTION: IRON GROUP TRANSITION METAL-REFRACTORY
METAL-BORON GLASSY ALLOYS
INVENTOR: RANJAN RAY

ABSTRACT OF THE DISCLOSURE
Low boron content alloys containing molybdenum are disclosed. The glassy alloys of the invention consist essentially of about 5 to 12 atom percent boron, one of the member selected from the group of 20 to 60 atom percent molybdenum and about 13 to 40 atom percent tungsten and the balance essentially one of the group consisting of cobalt, iron and nickel.
The glassy alloys evidence hardness values of at least about 1000 Kg/mm2, ultimate tensile strengths of at least about 330 Kpsi and crystallization temperatures of at least about 445°C. The high mechanical strength and high thermal stability of the glassy alloys of the invention render them suitable for use as reinforcement in composites for high temperature applications.

Description

7 ~

INVE~TION: IRON GROUP TRANSITION METAL-REFRACTORY
METAL-BORON GLASSY ALLOYS
INYEN~OR: RANJAN RAY
BAC~GROUND OF T~E INVENTIO~
1. Field of the Invention The invention relates to glassy alloys containing low boron content and molybdenum and/or tungsten in conjunc-tion with at least one other metal of the group cobalt, ironand nic~el.

2 Description of the Prior Art .

Chen et al. in U.S.P. 3,856,513, issued Decemb~r 24, 1974, have disclosed glassy alloys consisting essenti-ally of about 60 to 90 atom percent of at least one elementof iron, nic~el, cobalt, vanadium and chromium, about 10 to 30 atom percPnt of at least one element o phosphorus, boron and carbon and about 0.1 to 15 atom percent of at least one element o aluminum, silicon, tin, germaniumr indium, anti~
mony and beryllium. U2 to about one-f~urth of the metal may be replaced by elements which commonly alloy with iron and nickel, such as molybdenum, titanium, manganese, tungsten, zirconium, hafnium and copper. Chen et al. also disclose wires of glassy alloys having the general formula TiXj, where T is a transition metal and X is an element selected from the group consisting of phosphorus, boron, carbon, aluminum, silicon, tin, germanium, indium, beryllium and antimony, and where "i" ranges from about 70 to 87 atom ~ercent and llj~ ranyes from a~out 13 to 30 a~om percent.
More recently, Masumoto et al. in U.S.P. 3,986,867 issued October 19, 1976, have disclosed iron-chromium glassy alloys c~nsisting essentially o, about 1 to 40 atom ~ercent chromium, 7 to 35 atom percent of at least one of carbon, Doron and phosphorus and the b~lance iron. Up to about 40 atom percent of at least one o nickel and cobalt, up to 20 atom percent ~f at least one o~ molybdenum, zirconium, titanium and manganese and up to about 10 atom percent oE at least one o~ vanadium, niobium, tungsten, tantalum and copper may also be employed. Elements useful for improving mechanical properties include molybdenum, zirconium, tita-nium, vanadium, niobium, tantalum, tungsten, copper and manganese, while elements effective or improving the heat resistance include molybdenum, zirconium, titanium, vana-~ium, niobium, tantalum and tungstenO
Efforts to develop new compositions which are easily formed in the glassy state with superior mechanical properties and which at the same time retain high thermal stability are continuing. Subs~antial amounts of metalloid elements (typically 15 to 25 atom percent) are usually found most suitable for producing the glassy state under reason-able quenching conditions of at least about 105C/sec, con-sistent with forming a ductile product. However, such high metalloid content combined with a high refractory metal con-tent also may result in increasing brittleness of the glassy alloy in the as-quenched state.
SUMMA~Y OF_THE I~VENTION
In accordance with the invention, substantially totally glassy alloys containing a low boron content as a first component, plus molybdenum or tungsten as a second component in conjunction with one of the metals cobalt, iron and nickel are provided. The glassy alloys of the invention consist ~ssentially of about 5 to 12 atom percent boron, one only of the members selected from the group of 20 to 60 p~r-cent molybdenu~ and 13 to 40 atom percent tungsten and the balance essentially one of the group iron, cobalt and nickel.
In a more specific embodiment glassy alloys contaning all three of the metals cobalt, iron and nickel with the above specified boron and second component molybdenum, tungsten and mixtures thereof are provided wherein each of the metals cobalt, iron and nickel is present in an amount of at least about 5 atom percent, plus incidenta' impurities. The alloys of the invention evidence hardness values of at least about 1000 Kg/~m3, ultimate tensile strengths o at least about 330 Kpsi and crystallization temperatures of at least about 445C.
DETAILED DESCRIP~IO~I_OF THE INVENTIO~l The glassy alloys of the invention consist essen-tially of (I) about 5 to 12 atom percent boron together with (II) one only of the group consisting of molybdenum (about 20 to 60 wt~) and tungsten (about 13 to 40 wt~) with the balance being one of the group iron, cobalt and nickel or (III~ glassy alloys containing at least 5 atom percent of all three metals, cobalt, iron and nickel in amounts of at least 5 atom percent wherein the amount of molybdenum, tung-sten or mixtures thereof, is used in lesser quantities of about 5 to 15 atom percent together with boron in specified amounts of 5 to 12 atom percent. Preferably the boron is present in amounts of 8 to 10 atom percent and the molyb-denum and tungsten as component II in amounts of 30 to 50 atom percent and as component III in amounts of 8 to 12 atom percent. Examples of glassy alloys o the invention include ~i Mo45Bl0~ ~i55Mo35Blo' Ni60W30B10~ 70 20 10 Fe6oMo3oBlo~ Fe55M3s310/ Fe77wl5Bl8' 77 13 10t C5M40310' C~5M35alol Co6ow3oBlol 70 20 10 ~5 20 15 12 8~ Ni55Cl~el$~l2B8' C55Fel5Nil W ~lo B
It is seen that the gla5sy metal alloys of the in~ention comprise three components: the irst component is boron in amounts of from about 5 to about 12 atom percent;
the second component is a refractory metal of the group molybdenum in amounts of 20 to 60 atom percent and tungsten in amounts of from about 13 to 40 atom percent; and the third component comprising the balance of the alloy is selected from the group cobalt, iron and nickel The low boron content, the refractory metal con-tent and the third component are interdependent. ~hen theboron content is less than about 5 atom percent and both the refractory metal content and the iron group metal content lie within the limits speciLied, rapidly quenched ribbons llB~}

are not totally glassy. Rather, the rapidly quenched ribbons contain crystalline phases, which may comQrise a substantial fraction oE the material, depending on specific composition. The rapidly quenched ribbons containing crys-talline phases or mixtures of both glassy and crystallinephases have inferior mechanical properties, i.e., low ten~
sile strength, and are brittle. Ty~ically, such ribbons, having thicknesses up to 0.0015 inch, will racture if bent to a radius of curvature less than 100 times the tnickness.
~hen the boron content is greater than about 13 atom percent and both the refractory me~al content and the iron group metal content lie within the limits specified, rapidly quenched ribbons, while remaining fully glassy are, nevertheless, more brittle than ribbons having compositions within the scope o the invention. Typically, such ribbons fracture when bent to a radius of curvature less than about 100 times the thickness.
Similarly, for refractory metal concentrations less than than those listed above, compositions containing such low metalloid content do not form glassy alloys at the usual quench rates. For refractoey metal concentrations greater than those listed above, compositions containing such low metalloid content form brittle glassy alloys. If the alloys do not contain these metals in the respective proportions then, in general, the alloys do not form fully glassy ductile ribbons.
In contrast, ~hen the boron conten~ ranges from abou~ 5 to 12 together with the specified propor-tions of the refractory metal, molybdenum andtor tungsten, second compo-nent together with the third component of the group iron,cobalt and nickel, rapidly quenched ribbons are substan-tially totally glassy and possess superior mechanical pro-perties, i.e., high tensile strength and ductility. For exa~ple, glassy ribbons o the invention can be bent without fracture to a radius of curvature about 10 times the thic~-ness.
Use of refractory metal 21ements other than molyb-denum and tun~st~n and 1se of metalloids other than boron in the amounts given do not orm ductile glassy alloys at the usual quench rates. For example, re~lacing boron by carbon or silicon results in ~he formation o crystalline, rathe~
than glassy, phases.
The purity oE all elements i.s that found in normal commercial practice. However, it is contemplated that ~inor additions (up to a ~ew atom percent) o other alloying ele~
ments may be made wlthout an unacceptable reduction of the desired properties. Such additions may ~e made, for exam-ple, to aid the glass-forming behavior. Such alloying elements include the transition metal elements (Groups IB to ~IIB and VIII, Rows 4, 5 and 6 of the Periodic Table, other than the elements mentioned above) and metalloid elements (carbon, silicon, aluminum, and hosphorus).
The thermal stability of a glassy alloy is an important property in certain applications. ~hermal stab-ility is characterized by the time-temperature behavior oE
an alloy, and may be determined in part by differential thermal analysis (DTA). Glassy alloys with similar crystal-lization beha~ior as obser~ed by DTA may exhibit diferent embrittlement behavior upon exposure to the same heat treat-ment cycle. ~y DTA measurement, crystallization tempera-tures Tc can be accurately determined by heating a glassy alloy (at about 20 to 50C/min) and noting whether excess heat is evolved over a limited temperature range (crystal-lization temperature) or whether excess heat is absorbed o~er a particular temperature range (glass transition temperature). In general, the glass transition temper~ture i5 near the lowest, or first, crystalli~ation temperature T 1 and, as is conventional, is the temperature at which the v~scosity ranges rom about 1013 to 10l4 poise.
The glassy alloys of the invention are ~ormed by quenching an alloy melt of the appropriate composition at a rate of at least about 10 C/sec. A variety of techniques are available, as is well-~nown in the art, Eor fabricating rapidly-quenched continuous filament. Typically, a particu-lar composition is selected, powders of the requisite ele ments (or of materials that decompose to form the el~ments) in the desired proportions are mel~ed and homogenized, and the molten alloy i 5 rapidly quenched on a chill surface, such as a raoidly rotating cylinder.
The alloys of the invention are sl~bstantially totally glassy, as determined by X-ray diffraction. The term "glassy", as used herein, means a state of matter in which the component atoms are arranged in a disorde~ly array; that is, there is no long range order. Such a glassy alloy material gives rise to broad, diffuse diffraction peaks when subjected to electromagnetic radiation in the X-ray region (about 0.01 to 50 A wavelength). This is in contrast to cyrstalline material, in which the component atoms are arranged in an orderly array, giving rise to sharp diffraction peaXs. The term "substantially totally glassy"
as used herein means a state of matter havin~ crystalline and amorphous phases, the amorphous phase constituting at least about 80 percent of the combined phases. Thermal sta-bility of the alloys improves as the degree o amor~housne~s thereof approaches 100%. Accordingly, totally glassy alloys, possessing a single, amorphous phase constituting 100% of the component atoms are preferred.
The glassy alloys of the invention evidence hard-ness values of at least about 1000 Kg/mm , ultimate tensile strengths of at least about 350 Kpsi and crystallization temperatures of at least about 445C. Preferred alloy com-positions consist essentially of about 50 to 65 atom percentof one of the iron group meta's of iron, cobalt and nickel, about 13 to 35 atom oercent of the remaining two iron gro~p metals, about 8 to 12 atom percent of at least one of molyb-denum and tungsten and about 8 to 10 atom percent boron.
The alloys having such preferred compositions are especially-capable of being fabricated as good quality, ductile-ribbons exhibiting high tensile strength.
The high mechanical strength and high thermal stability of the glassy alloys of the invention render them suitable for use as reinforcement in composites for high temperature applications.
XA~PL~S
Alloys were prepared from constituent elements of high purity (99.9%). The elements wi~h a total weight o 30 g were melted by induction heat2r in a quartz crucible under vacuum of 10 3 Torr. The molten alloy was held at 150 to 200C abo~e the liquidus temperature Eor 10 min and allowed to become completely homogenized beore it ~as slowly cooled to the solid state at room temperature. The alloy was fractured and examined Eor complete homogeneit~.
About 10 g of the alloys was remelted to 150C
above liquidus temperatures under vacuum o 10 3 Torr in a ~uartz crucible having an orifice of 0.010 inch diameter in the bottom. The chill substrate used in the present work was beryllium-copper alloy in a heat-treated condition having moderately high strength and thermal conductivity.
The substrate material contained 0.4 to 0.7 wt% beryllium, 2,~ to 2.7 wt~ cobalt and co~per as balance. The substrate was '~ept rotating at a surface speed o 4000 ftJmin. The substrate and the crucible were contained inside a vacuum chamber evacuated to 10 3 Torr.
The melt was spun as a molten jet by applying argon pressure of 5 psi over the melt. The molten jet impinged vertically onto the internal surface of the rotat-ing substrate. The chill-cast ribbon was maintained in good contact with the substrate by the centrifugal Eorce acting on the ribbon against the surface. The ribbon was ejected off the substrate by nitrogen gas at 30 psi, two-thirds cir-cumferential length away from the point of jet impingement.
During the metallic glass ribbon casting operation, the vacuum chamber was maintained under a dynamic ~acuum of 20 Torr. The substrate surface was polished with 320 grit emery paper and cleaned and dried with acetone prior to the start of the casting operation. The as-cast ribbons were found to have good edges and surfaces. The ribbons had t'ne following dimensions: 0.001 to 0.0012 inch thic~ness and 0.01~ to 0.020 inch width.
The degree of glassiness ~as determined by X-ray diffraction~ A cooling rate of at least about 10 C/sec was attained by the quenching process.

~ ardness was measured by the diamond pyramid tech-ni~ue using a ~ickers-type indenter, consisting of a diamond in the form of a square-base pyramid ~ith an included angle of 136 between opposite faces. Loads o~ 100 g were applied.
Crystallization temperature was measured by diEq~ential thermal analysis at a scan rate of about 20C/min. Ultimate tensile stren~th was measured on an Instron machine u~ing ribbons ~ith unpolished edges. The gauge length of the specimens was 1 inch and the cross-head speed was 0.02 in/min. 2 The following values of hardness in Kg/mm , ulti-mate tensile strength in Kpsi and crystallization temp~ra-ture in C, listed in ~ables I-IV below, ~ere measured Eor a number of compositions falli~g within the scope of the invention.

Mechanical and Ther~al Properties of Ni-~o-B
and Ni-W-B Glassy Alloys o the Invention Composition Hardness, Ultimate Tensile Crystallization (atom ~ercent) Kg/mm2 Stren~th, K~si Te~erature, ~C
Ni60Mo35B5 1186 Ni60~30B10 1097 Ni57M35B8 1206 490 613,673 Ni55~35B10 1246 380 610,655 Ni53MO~oB7 1310 Ni;oMo4oBlo 1240 390 825 Ni45M45810 1330 530 850 Ni42Mo5088 1401 806,33~,896 Ni35~55B10 1452 846 Ni33M55B12 1465 Ni32M60B8 1505 Ni31M57812 1465 860,890 Ni7ow22B8 1246 330 562 Ni7o-~2oBlo 1159 330 546 ~i66W22B12 1287 Ni6ow35B5 1032 Ni6or~3oBlo 1222 430 544 _9_ TABLE II
Mechanical and Thermal Properties of Fe-Mo-B
and Fe-W-3 Glass~ Alloys of the Invention Ultimate Composition Hardness, Tensile Crystallization (atom percent) Kq/mm2 Stren~th, Kpsi Tem~erature, C
Fe65.~o25B10 1308 475615;680 Fe60Mo35B5 1354 Fe60Mo30B10 1402 486 Fe55Mo4 oB s 1682 Fe55Mo35B10 1532 Fe5oMo38B12 lS89 Fe77W15B8 1330 420658;867 Fe75W20B5 1465 625;869 Fe7S~13B12 1315 Fe67W2SB8 15Q5 TABLE III
~echanical and Thermal Properties of Co-Mo-B and Co-W-B Glassv Alloys of the Invention Composition Hardness, Ultimate Tensile Crystallization (atom ~ercent) Kg/mm2 Strength, Kpsi Temperature, C
Co70Mo20B10 1266 Co66Mo26B8 1330 39S603;639 Co6oMo35BS 1131 CO58Mo3gB12 1402 4SS 670 Co55M35B10 1450 483 684 Co50Mo40B10 1510 467 785 Co40Mo50B10 1560 Co77W15B8 Co70W20 10 1426 Co68W25B7 1410 460641;665 C60W30B10 lS9S SlS720;780;865 Co55~0B5 1309 TABLE I i7 ~lechanical and Thermal Properties oE
(Fe,Co,Ni)~ o,',~)-a Glassy Alloys o the Invent.ion Crystal-~ltimate lization Composition Hardness, Tensile Tempera-(atom ~ercent) Kg/mm2 _ Strength, Kpsi ture, ~C
Fe55Co2oNil5Mol2 8 1064 396 445 Fe55ColoNil5;~ol2 8 1159 410 465 Fe55COlONils~o6w6B8 1186 Fe65ColoNilo~o4w3B8 1048 387 480 Fe75Co5Ni5Mo4w3B8 106~
Fe67ColoNilo~o4w3B6 1032 450 Fe57ColoNil5Mol2B6 1114 350 Fe70col~Ni8~o5B7 1000 Fe65ColoNil~Molo 5 1064 463 Fe65Co5~iswlsBLo 1225 553 Fe57C20Nilow5 8 1001 472 Ni45Co2oFel~w6~lo6B8 1159 478 Ni55coloFels~lol2B8 1114 368 458 Ni65ColoFelo~o7B8 1064 Ni57Fe10cl5~l2B6 1120 Co45Ni20~elswl2B8 1186 403 Co,5Fel5Ni10W6i~6B8 1146 505 .
Co65Felo~iloMo? 8 1080 496 Co57NilOFelsMol2 6 1201 Co55NiloFeldl~olsBlo 1225 425 Table V sets forth compositions outside the scope of the invention and the results of structural analysis by ~-ray diffraction in chill cast ribbons of these composi-tions prepared as above, and the brittleness of the rlb~ons.

8~

T~BLE V
Results of Chill Casting of Alloy Compositions Outsid~ tne Scooe of the Present Invention Structure by X-ray Elements Charac-5 Composition analyses Outside teristics (Atom of Chill Sco~e of of the oercent) Cast Ribbons Invention Rlbbon~
Fe50Ni2oco22B8 crystalline ~o,W hrittle ~e40Ni3oco22~8 crystalline ~o,W brittle Ni5oFe2oco2288 crystalline ~o,W brittle C50Ni20Fe22B8 crystalline ~o,W brittle Fe70Niloco2Moloa8 60% crystalline + Co brittle Fe Co W B 60~ crystalline + Ni extremely 55 20 15 10 40% glassy brittle Ni50co3oMolo 10 crystalline Fe brittle 50 20Ni20~2B830~ crystall ne + Mo or W brittle Fe70~il0C8w2Bl060~ crystall ne + `~lo or W brittle Fe50Ni27colsMo5B350% glassy B brittle 20 Ni50Fe28coloMosws 2crystalline B brittle

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A substantially totally glassy alloy consist-ing essentially of (I) about 5 to 12 atom percent boron and (II) a member selected from the group consisting of about 20 to 60 atom percent molybdenum and about 13 to 40 atom percent tungsten with the balance being essentially a metal of the group consisting of cobalt, iron and nickel.

2. The glassy alloy of claim 1 wherein the boron is present in an amount of 8-10 atom percent and the molybdenum and tungsten in member II is present in amounts of 30 to 50 atom percent respectively.

3. A substantially totally glassy alloy consist-ing essentially of about 5 to 12 atom percent boron, a member selected from the group consisting of 30 to 60 atom percent molybdenum and about 20 to 35 atom percent tungsten and the balance essentially nickel plus incidental impurities.

4. The glassy alloy of claim 3 having a composi-tion selected from the group consisting of Ni57Mo35B8, Ni55Mo35B10, Ni45Mo45B10, Ni42Mo50B10, Ni42Mo50B8, Ni70W22B8, Ni70W20B10 and Ni60W30B10.

5. A substantially totally glassy alloy consist-ing essentially of about 5 to 12 atom percent boron, a member selected from the group consisting of about 25 to 40 atom percent molybdenum and about 13 to 25 atom percent tungsten and the balance essentially iron plus incidental impurities.

6. The glassy alloy of claim 5 having a composi-tion selected from the group consisting of F360Mo30B10, Fe55Mo35B10, Fe77W15B8 and Fe77W13B10.

7. A substantially totally glassy alloy consist-ing essentially of about 5 to 12 atom percent boron, a member selected from the group consisting of about 20 to 50 atom percent molybdenum and about 15 to 40 atom percent tungsten and the balance essentially cobalt plus incidental impurites.

8. The glassy alloy of claim 7 having a composi-tion selected from the group consisting of Co66Mo26B8, Co55Mo35B10, Co50Mo40B10 and Co60W30B10.