13.10/2023
POLEMA presented at the“BIOTECHMED” its innovative medical products
11.07/2023
POLEMA at INNOPROM in Ekaterinburg
Molybdenum alloy MoW30-PM, MoW10-PM, MoW-2-PM, MoWCu-PM, MoLa-PM, MoY-PM products
Some properties of molybdenum that are important for industrial use include its high melting point, high elasticity modulus, low temperature linear expansion coefficient, good plasticity at low and room temperatures, heat-resistance, high electric and heat conductivity, relatively small capture cross-section of thermal neutrons, and almost half the density of wolfram.
Some drawbacks of molybdenum as a construction metal are its susceptibility to oxidation at temperatures higher than 500-700 оС and the fact that it is not sufficiently heat resistant to be used in conditions of extremely high temperatures and lengthy loads. Alloying of molybdenum has practically no effect in terms of eliminating the first drawback, but does make it possible to significantly raise the recrystallization temperature, durability and creep resistance at high temperatures, and, for dispersive hardeing—for example, using lanthanium oxide—to increase heat resistance and improve plastic properties (lower the fraility threshold).
Below is the list of products made from alloyed molybdenum:
- Hot-rolled sheet from molybdenum- tungsten alloy MoW-PM.
- Extruded and tooled products from molybdenum- tungsten alloy MoW-2-PM.
- Crucibles from molybdenum- tungsten alloy.
- Products from molybdenum, tungsten and their alloys for high-temperature furnaces.
- Products from the molybdenum- tungsten alloy MoW10-PM for sputtering targets.
- Rolled stock and products from lanthanium-treated molybdenum MoLa-PM.
- Stock materials made from MoWCu-PM.
- Tooled stock materials made from MoY-PM molybdenum alloy.
1. HOT-ROLLED SHEETS FROM MoW-PM MOLYBDENUM- TUNGSTEN ALLOY
Use
The molybdenum alloy MB MoW, strengthened by forming a solid solution with tungsten (nominal composition by mass percentage: Mo 70%, W 30%, content of alloying component ± 2%), boasts a higher recrystallization temperature than molybdenum (as high as 1200 оС with a deformation ratio of 90%), resistance to high temperatures, resistance to corrosion and creep (creeping at high temperatures).
Rolled stock made from MoW alloy is used to make components for high-temperature furnaces, electrodes for power semiconductors, and other purposes.
| Thickness, mm | Width, mm | Length, mm |
| 0,8-0,9 | From 30 to 300 | From 80 to 1000 |
| 1,0-3,0 | Up to 500 | Up to 1000 |
| 3,1-15 | Up to 500 | Up to 1000 |
Sheets are delivered annealed for internal stress removal and with tested microstructure.
|
Sheet thickness, mm |
Rupture strength σв, Н/mm2 (kgf /mm2), minimum |
δ, %, minimum |
| Sheet properties, transversal direction | ||
| 0,8-0,9 | 830 (85) | 8 |
| 1,0-3,0 | 780 (80) | 8 |
| 3,1-6,0 | 780 (80) | 6 |
Mechanical properties of small-scale sheets (thickness of up to 110 mm, length up to 250 mm) are set based on the client's request.
2. EXTRUDED STOCK FROM МВ-2-МP ALLOY
Use
Products made from strengthened MoW-2-PM molybdenum-tungsten alloy are used to produce components operating in difficult, stressed environments at increased temperatures (up to 2100 оС).
Stock is produced using powder metallurgy, with technical support from specialists at the Central Science and Research Institute for Materials (OAO CSRIM) and the Powder Metallurgy Institute at the Central Science and Research Institute for Iron Metallurgy (PMI FGUP named after I.P. Bardin “CSRIIM”).
Stock dimensions
Tooled stock is produced in the following dimensions:
round, with diameters of Ø 36, 53, and
rectangular, cut to 64х46, with a length of at least 350 mm.
The surface coarseness of tooled products does not exceed 6.3 microns.
At the client's request, products with other dimensions can be produced.
Stock is delivered having undergone thermal treatment and with testing for microstructure and mechanical properties.
|
Dimensions, shape, mm |
Thermal treatment variant * | Specimen type** | Mechanical properties (minimum) at testing temperature | |||||
| 20о С | 150о С | 1800о С | ||||||
| σв, MPa | δ, % | σв, MPa | δ, % | σв, MPa | δ, % | |||
| 64х46 | А | lengthwise | 650 | 5,0 | n/a | n/a | 50 | 5,0 |
| transverse | 500 | 1,0 | 500 | 2,0 | 50 | 5,0 | ||
| В | lengthwise | 500 | 5,0 | n/a | n/a | 45 | 5,0 | |
| transverse | 450 | 2,0 | 450 | 2,0 | 45 | 5,0 | ||
| Ø 53 | А | lengthwise | 650 | 5,0 | n/a | n/a | 50 | 5,0 |
| transverse | 500 | 0 | 500*** | 2,0*** | 50*** | 5,0*** | ||
| Ø 36 | В | lengthwise | 500 | 5,0 | n/a | n/a | 45 | 5,0 |
| transverse | 450 | 0 | 450*** | 2,0*** | 45*** | 5,0*** | ||
Notes:
* Thermal treatment variant
А – at 1300 о С
В – at 1400 о С
** Specimen type:
lengthwise, transverse – direction of the specimen's cut with regard to the direction of extrusion.
*** properties not determined, guaranteed by the technology
n/a – properties not determined
With a relative elongation of δ ≥ 2%, a conditional yield limit of σ0,2 is achieved. Typical values for mechanical properties exteed the guaranteed parameters by 15-35 %.
| d , мм * | ε , % * * | σв, MPa | δ, % | σв, MPa | δ, % |
| 20о С | 1800о С | ||||
| 53 | 75 | 760 | 11,8 | 57,6 / 54,8 | 22,6 / 14,0 |
| 36 | 79 | 790 | 16,0 | 62,0 / 61,2 | 24,0 / 14,0 |
Note:
* rod diameter
** deformation ratio
Figures including fractions (/): the numerator indicates data obtained during testing of lengthwise specimens, and the denominator indicates data for transverse specimens.
3. MoW30-PM CRUCIBLES FROM MOLYBDENUM- TUNGSTEN ALLOY
Use
MoW30 molybdenum-tungsten alloy, strengthened with a solid solution of tungsten, features temperature resistance and creeping resistance that is higher than molybdenum, and higher machinability than tungsten.
TMB30-MP crucibles made from sintered and forged molybdenum-tungsten alloy are used primarily to melt corundum in technologies for growing extremely pure sapphire monocrystals.
Chemical composition of crucibles
Molybdenum is the base, with 28-32% tungsten. The alloy may be additionally strenghened with admixtures of B, Hf, Y, Zr, C.
Shape and dimensions
Crucibles are produced in accordance with plans. The shape and dimensions are agreed upon with the client. Surface roughness of tooled crucibles does not exceed Rz 6.3.
Crucible density:
Sintered MoW30-PM crucibles – at least 10.9 g/cm3
Forged MoW30-PM crucibles – at least 11.2 g/cm3
Recommendations on crucible storage and use.
Recommendations on the use, transport and storage of crucibles can be found in the section entitled “Tungsten. Tungsten Crucibles”.
4. PRODUCTS MADE FROM MOLYBDENUM, TUNGSTEN AND THEIR ALLOYS FOR USE IN HIGH-TEMPERATURE FURNACES
Use
Products made from molybdenum, tungsten V-MP, and the molybdenum alloys MoW30-PM (MoW30), MoLa-PM are used to outfit vacuum and hydrogen furnaces, the heat zones of units for smelting quartz glass and growing sapphire monocrystals, furnaces for the annealment of uranium fuel in the manufacture of fuel rods, and for the production of components for high-temperature heat exchangers, thermoelectric converters, and other devices that operate at high temperatures.
Shape and manner of production
Products are made in sintered form, or from deformed (by forging or rolling) stock (sheets, plates, forced products, rods) according to the client's plans (drafts) or according to a manner of production, geometric dimensions and allowances for dimensions and surface roughness submitted by the client.
Products are made in simple shapes: tooled discs, slabs, rings, plates, substrata, bearing plates, rods, or electrodes; or, in complex shapes: thermal screens, radiators, boats, fastening details, etc. Additional requirements regarding product specifications are set based on the client's request.
Recommendations on use
Before use, thermal screens and other products used in a customer's vacuum furnaces should be annealed in a vacuum of р<10-4 mmhg (torus) in the following manner:
- heat to 1000 оС for over a period of at least 3 hours,
- hold at approximately 1000 оС for at least 1 hour,
- heat to 1400-1500 оС over a period of at least 1 hour,
- hold at approximately 1400-1500 оС for at least 1 hour,
- heat to 2000-2200 оС over a period of at least 1 hour,
- hold at approximately 2000-2200 оС for at least 1 hour,
- cool the products in the furnace.
During use, the products should not be subjected to shocks.
5. PRODUCTS FROM MOLYBDENUM- TUNGSTEN ALLOY MoW10-PM FOR SPUTTERING TARGETS
Use
Products made from MoW30-PM (MoW10) molybdenum-tungsten alloy are used as sputtering targets in technologies of thin films to produce electronic components and other functional coatings, as well as to produce components for high-temperature vacuum and hydrogen furnaces.
| Element | Mass percentage |
| Mo+W | 99,95% minimum |
| W | (10,0 ± 1,0) % |
| Admixtures, ppm, maximum | |
| Fe | 100 |
| Al | 50 |
| Ni | 50 |
| Si | 100 |
| Total metallic admixtures | 500 |
| C | 100 |
| O | 70 |
| N | 50 |
Other requirements for the products' chemical composition may be agreed upon based on the client's requests.
Product shape and dimensions
Products are made in the form of tooled plates, discs, rings, cylinders (rods), and in simple and complex shapes.
The shape and dimensions of products and surface characteristics are determined based on plans (drafts) agreed upon with the client.
6. ROLLED STOCK AND PRODUCTS MADE FROM MoLa-PM LANTHANUM-TREATED MOLYBDENUM
Use
In the late 1990's, a molybdenum alloy dispersion-strengthened with lanthanum oxide—so-called ODS-Mo—won widespread recognition and use abroad. POLEMA produces an alloy of this kind, under the brand MoLa-PM (lanthanum-treated molybdenum).
ODS-Mo is recommended as a more stable material for replacing other molybdenum alloys in a number of spheres for use in high (1600-1800 оС and higher) temperatures:
• electric engineering: radiators, thermal screens, circuit breaker parts and incandescent lamp parts;
• atomic energy and power systems: creep-resistant boats for smelting nuclear fuel, high-temperature springs, high-temperature convertors, vanes and tracks for cyclical turbines;
• the space and rocket industry: parts for jet apparatuses, high speed engines, and rocket combustion chambers;
and other industries.
Lanthanum oxide, introduced into the system and enveloping molybdenum grains, serves as a displacement barrier to dislocations during the deformation process, which allows the alloy structure to stabilize; with small grain sizes, it ensures durability and resistance to creep at high temperatures. Other well-known industrial alloys—for example, stabilized with carbides of titanium and zirconium—of the type Мо-TZM (Mo-0,5Ti-0,08Zr, 0,01-0,04C mass %) и Mo-TZC (Mo-1,2Ti-0,3Zr, 0,25C mass%), are less stable, since at high temperatures the carbide constituent becomes coarse or breaks down within the molybdenum matrix.
Molybdenum alloy that has been dispersion-reinforced with lanthanum oxide has the following advantages over molybdenum: a significantly lower cold shearing threshold following annealment (with internal stress removal), higher durability at room temperature, high plasticity in a recrystallized state, more than 1.6 times greater durability at 1600оС, and significantly higher (an order of magnitude greater) resistance to deformation during tests for long-term durability at 1800 оС when compared with unalloyed molybdenum obtained through arc melting or the PM method.
| Element | Mass percentag |
| Mo | основа |
| La | 0,40 ± 0,07 % |
| Admixtures, ppm, maximum | |
| Fe | 100 |
| Al | 30 |
| Ni | 50 |
| Si | 50 |
| Mg | 20 |
| Na | 30 |
| K | 80 |
| Ca | 40 |
| W | 130 |
| Total metallic admixtures | 500 |
| C | 100 |
Product shape and dimensions
Products made from MoLa-PM are produced in the form of rolled sheets, slabs, plates, discs, forged rods, boats, screens, and radiator components.
Sheet it produced with tickness of 0.5 mm or greater.
Below are the guaranteed allowances for dimensions and surface quality of rolled stock:
thickness ± 0,10 %;
width ± 0.8 mm;
length ± 1,6 mm per 304,8 mm of length;
roughness of a milled or ground surfaces shall not exceed 40.
Concrete dimensions and allowances for thickness, width, and length of rolled stock, forged stock or tooled products, including requirements for surface roughness, are set in accordance with client requests. Unless otherwise specified, the roughness of a milled or ground surface does not exceed Rz40.
Products with complex shapes are produced based on plans.
| Width, mm | Tensile strength σв, Н/mm2 (kgf/ mm2) | Relative elongation δ, % |
| Minimum | ||
| From 1.0 to 2.0 mm inclusive | 690 (70) | 5 |
| > 2.0 to 4.0 mm inclusive | 690 (70) | 10 |
| > 4.0 to 6.0 mm inclusive | 640 (65) | 8 |
Sheets with a thickness of less than 1 mm undergo bend testing with a bending angle of at least 90о.
| Material | Test temperature, оС |
Tensile strength σв, kgf/ mm2 |
Relative elongation δ, % |
| Sheet Mo-La-PM 2,0-3,0 | 20 | 88-98 | 10-12 |
| Rod Mo-La-PM Ø 9,5 | 20 | 74-75 | 30-35 |
| Rod Mo-La-PM Ø 20 | 1400 | 8,2-9,0 | 31-39 |
| 1800 | 6,3 | 9,2 |
fig. 1Mo-La-PM material dispersion-strengthened with lanthanum oxide shows excellent resistance to creeping. Its operational life in the form of screens and radiators in resistance furnaces is more than twice the useful life of components made of pure molybdenum. The material maintains its fibrous structure throughout extended operation at high temperatures. Moreover, radiator and screen components made of 0.4-0.5 mm maintain plasticity at room temperature in a recrystallized state.
*Fig.1: Microstructure of MoLa-PM sheet with a thickness of 1 mm Distribution of lanthanum in the structure of dispersion-strengthened molybdenum MoLa-PM.
7. STOCK MADE FROM MoWCu-2-PM MATERIAL
Stock is produced using powder metallurgy with technological support from specialists at the Institute of Powder Metallurgy at the Central Science and Research Institute for Iron Metallurgy (IPM FGUP “CSRIIM” named after I.P. Bardin).
Use
Compositional material based on molybdenum-tungsten alloy infiltrated with copper shows durability at high temperatures and resistance to gas erosion. It is used to make parts for new equipment operating at high temperatures and with dynamic loads.
Material characteristics
Currently, MoWCu-2-PM material is used to produce tooled stock in cylindrical form with a diameter of 50 or 70 mm. At the client's request, products of other shapes and dimensions can be produced.
The stock's density following infiltration of the sintered frame is at least 11.0 g/ cm3.
8. STOCK MADE FROM MoY-PM MOLYBDENUM ALLOY
Stock is produced using powder metallurgy with technological support from specialists at the Institute of Powder Metallurgy at the Central Science and Research Institute for Iron Metallurgy (IPM FGUP “CSRIIM” named after I.P. Bardin).
Use
Dispersion-strengthened deformed MoY-PM molybdenum alloy is intended for use in preparing parts capable of working for extended periods at high temperatures.
Material characteristics
Currently, tooled stock made from MoY-PM alloy is produced in the form of rods with a diameter of 66 mm and a length of no less than 310 mm, and with a diameter of 90 mm and a length of no less than 230 mm. Surface roughness does not surpass 6.3 microns. At the client's request, products of other dimensions can be made according to plans.
Product microstructure is monitored using a optical microscope, while the absence of internal flaws is checked for using ultrasound.
| Material | Minimal mechanical properties of semifinished products in end-fire direction based on temperature, оС | |||
| 20 | 1800 | |||
| σв, Н/mm2 (kgf/ mm2) | δ, % | σв, Н/mm2 (kgf/ mm2) | δ, % | |
| MoY-PM | 500 (51) | 8,0 | 27,0 (2,75) | 20 |
