US3891431A - Method of, and apparatus for, controlling the crystalline structure of alloys, and alloys so produced - Google Patents

Method of, and apparatus for, controlling the crystalline structure of alloys, and alloys so produced Download PDF

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Publication number
US3891431A
US3891431A US244652A US24465272A US3891431A US 3891431 A US3891431 A US 3891431A US 244652 A US244652 A US 244652A US 24465272 A US24465272 A US 24465272A US 3891431 A US3891431 A US 3891431A
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Prior art keywords
temperature gradient
alloys
phase
zone
alloy
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Expired - Lifetime
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US244652A
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English (en)
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Peter Sahm
Renata Sebalj-Novosel
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BBC Brown Boveri AG Germany
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Bbc Brown Boveri & Cie
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working

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  • ABSTRACT I The crystalline structure of an alloy having a structure [52] 7 823754 23 which is at least partially eutectic is controllable by j heat-treatment, by forming in a body of the alloy a [51] 'f gg g f gg i 14 zone of high temperature gradient between a melting 1 Fla d 0 earc 75 is a 5 region and an adjacent solidification region.
  • the rate I of progress of said high temperature gradient over the body may be controlled whereby to influence a prede- [561 uNlTE g gg xg gs gi TENTs termined crystallization in the matrix of the eutectic.
  • the invention relates to a method of controlling, by heat treatment, the crystalline structure of alloys which have a structure which is at least partially eutectic.
  • the invention also includes an apparatus for carrying out the method, and also a determined application of the method in the cases of certain alloy compositions.
  • alloys which have a structure which is at least partially eutectic are of great technological interest.
  • the same therefore also applies to the heat treatment of such alloys with the object of directing their structure towards determined improvements of properties.
  • the aim of such improvements is in many cases the attainment of a uniform and/or symmetrical crystalline structure of the eutectic. particularly in respect of the shape and arrangement of the crystals embedded in the matrix of the eutectic.
  • the problem underlying the invention therefore consists in providing a method of heat treatment and an appertaining apparatus or a corresponding application of the method whereby structure control of the kind mentioned can be achieved.
  • the method according to the invention for the solution of the problem is characterized in that a zone with a high temperature gradient between a melting region and a solification region is produced in the alloy.
  • the apparatus according to the invention for the solution of the problem is characterized in that a heating apparatus acting on the workpiece and a cooling apparatus. likewise acting on the workpiece are disposed a short distance apart so as to form a transition region with a high temperature gradient.
  • a method of the kind described above can be applied by forming the zone having a high temperature gradient between a melting zone and a solification zone in an alloy the eutectic portion of which has a first. at least substantially isotropic. phase and a second. comparatively highly anisotropic. crystalline phase.
  • FIG. 1 is a diagrammatical longitudinal section of an apparatus for the continuous heat treatment ofa workpiece in wire form
  • FIG. 2 is a partial longitudinal section in the region II in FIG. 1, on a larger scale;
  • FIG. 3 shows a part of a ternary phase diagram for a CoCr-C system
  • FIG. 4 shows a microscopic polished section of an alloy from the diagram shown in FIG. 3, produced by the conventional method.
  • FIG. 5 shows a corresponding polished section after continuous treatment with a high temperature gradient.
  • a workpiece l which is in wire form and is surrounded by a thinwalled.
  • high-temperature resistant tube 2 in the manner illustrated in FIG. 2, is inserted into a holder of the push-rod 3 of a driving device indicated by a double arrow 4.
  • the drive device is sealed by means of a bellows 5 in relation to the gas-carrying system of the apparatus, which system comprises a bell 6, an inlet pipe 7, and an outlet pipe 8.
  • an inert gas for example argon
  • the sheathed workpiece 1 passes in the downward direction through the passage of a heating device 11 and, by way of an intermediate space 16, penetrates into a cooling bath 17.
  • the heating device 1 for example a high frequency induction heater, comprises a winding 12 together with a susceptor 14 which surrounds the workpiece, and which for example is made of tantalum, and an outer heat shield l3, made for example of alumina.
  • the heating device can be raised and lowered by means of an adjusting device, indicated diagrammatically by a double arrow 15, whereby the height of the intermediate space 16 is varied accordingly. For a given temperature difference between the outlet of the heating device ll and the inlet of the cooling bath 17, the temperature gradient acting in the intermediate space 16 can thus be adjusted.
  • control is also optionally possible for the purpose of maintaining a predetermined ratio between, on the one hand, the difference in temperature between the heating device and the cooling device, and, on the other hand, the distance between these two devices.
  • the temperature of the cooling bath which latter may conveniently consist of a molten bath, for example. of a eutectic alloy having a correspondingly low melting point, is controlled additionally.
  • a current of a heat transfer medium for example water. is provided in a cavity which surrounds the cooling bath l7 and is formed between an outer tube 9 and an inner tube 10 and which is provided with connecting pipes 20 and 21.
  • the height of the intermediate space and, consequently, if the temperature difference remains unchanged, the value of the temperature gradient between the melting zone and the solidification zone can be adjusted by raising or lowering the level of the cooling bath or, in conjunction with suitable measuring and control elements, can also be automatically controlled.
  • a suitable inlet and outlet device for the cooling medium is indicated in FIG. 1 by the double arrow 19 at the cooling medium connection 18.
  • FIG. 3 The relative region of a phase diagram of a ternary system of this kind is shown in FIG. 3. This relates to a CoCr-C system with a carbide phase of the variable composition Cr Co,C in accordance with region a, and also with a metallic matrix of the composition Co, ,,-,,Cr ,-C,, in accordance with region 11. A eutectic channel e extends between these regions. Investigations have shown that the symmetrizing effect or the field of application of the method requires the presence of an at least substantially isotropic crystalline phase and a relatively highly anisotropic crystalline phase in a eutectic.
  • values of the temperature gradient above about 2500Clcrn have been found particularly favorable. and the effect was also observed up to values of l0.000C/cm. so that no restrictive limitation in the upward direction can be seen.
  • the effect of morphological structure symmetrization was observed at speeds of solidification between and 100 cm/hour. Relatively high values of speed of solidification or speed of passage of a workpiece can therefore be attained, while small diameters or layer thicknesses in the case of workpieces in wire or strip form facilitate the attainment of a high temperature gradient.
  • the improvement comprising symmetrizing said structure by passing said body through a melting zone and a solidification zone, wherein the temperature gradient between the melting zone and the solidifcation zone is at least 2.500C/cm, and wherein the speed of said body is advanced through said zones is a rate of from l-lOOcm/hr.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Furnace Details (AREA)
  • Heat Treatment Of Steel (AREA)
US244652A 1971-05-10 1972-04-17 Method of, and apparatus for, controlling the crystalline structure of alloys, and alloys so produced Expired - Lifetime US3891431A (en)

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CH688271 1971-05-10

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US3891431A true US3891431A (en) 1975-06-24

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US (1) US3891431A (2)
DE (1) DE2127968A1 (2)
FR (1) FR2139333A5 (2)
GB (1) GB1376382A (2)
IT (1) IT955315B (2)
SE (1) SE387370B (2)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4609402A (en) * 1985-10-28 1986-09-02 Iowa State University Research Foundation, Inc. Method of forming magnetostrictive rods from rare earth-iron alloys

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2719799A (en) * 1952-11-13 1955-10-04 Rca Corp Zone melting furnace and method of zone melting
US2739088A (en) * 1951-11-16 1956-03-20 Bell Telephone Labor Inc Process for controlling solute segregation by zone-melting
US2855335A (en) * 1955-01-14 1958-10-07 Int Standard Electric Corp Method of purifying semiconductor material
US3030194A (en) * 1953-02-14 1962-04-17 Siemens Ag Processing of semiconductor devices
US3060123A (en) * 1952-12-17 1962-10-23 Bell Telephone Labor Inc Method of processing semiconductive materials
US3124452A (en) * 1964-03-10 figure
US3496033A (en) * 1967-06-05 1970-02-17 United States Steel Corp Method and apparatus for controlling annealing furnaces
US3498851A (en) * 1964-12-17 1970-03-03 Nippon Musical Instruments Mfg Method for producing an anisotropic permanent magnet material
US3536540A (en) * 1966-11-21 1970-10-27 Aluminium Francais Process for alleviation of stresses in hardened alloy products
US3552953A (en) * 1969-01-10 1971-01-05 United Aircraft Corp Cobalt-chromium base alloy and articles produced therefrom
US3564940A (en) * 1968-06-05 1971-02-23 United Aircraft Corp Anisotropic polyphase structure of monovariant eutectic composition

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124452A (en) * 1964-03-10 figure
US2739088A (en) * 1951-11-16 1956-03-20 Bell Telephone Labor Inc Process for controlling solute segregation by zone-melting
US2719799A (en) * 1952-11-13 1955-10-04 Rca Corp Zone melting furnace and method of zone melting
US3060123A (en) * 1952-12-17 1962-10-23 Bell Telephone Labor Inc Method of processing semiconductive materials
US3030194A (en) * 1953-02-14 1962-04-17 Siemens Ag Processing of semiconductor devices
US2855335A (en) * 1955-01-14 1958-10-07 Int Standard Electric Corp Method of purifying semiconductor material
US3498851A (en) * 1964-12-17 1970-03-03 Nippon Musical Instruments Mfg Method for producing an anisotropic permanent magnet material
US3536540A (en) * 1966-11-21 1970-10-27 Aluminium Francais Process for alleviation of stresses in hardened alloy products
US3496033A (en) * 1967-06-05 1970-02-17 United States Steel Corp Method and apparatus for controlling annealing furnaces
US3564940A (en) * 1968-06-05 1971-02-23 United Aircraft Corp Anisotropic polyphase structure of monovariant eutectic composition
US3552953A (en) * 1969-01-10 1971-01-05 United Aircraft Corp Cobalt-chromium base alloy and articles produced therefrom

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4609402A (en) * 1985-10-28 1986-09-02 Iowa State University Research Foundation, Inc. Method of forming magnetostrictive rods from rare earth-iron alloys

Also Published As

Publication number Publication date
FR2139333A5 (2) 1973-01-05
IT955315B (it) 1973-09-29
GB1376382A (en) 1974-12-04
SE387370B (sv) 1976-09-06
DE2127968A1 (de) 1972-11-16

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