Конструкциялық материалдар және термоөңдеу Конструкционные материалы и термообработка Constructional materials and heat treatment Учебное пособие для специальности: 5В071200– «Машиностроение»

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Layered CCM are the designs consisting of a metal basis with the put ceramic 
covering. The ceramic component of such material can be put on metal with 
enameling, gas-flame dusting, and decomposition of salts of metals with their 
subsequent oxidation. 
Ceramic-metal materials are subdivided on: 
- porous metal ceramics having residual porosity within 15-50% (antifrictional 
and "sweating" materials, filters). 
- compact metal ceramics - magnetic, frictional and electrotechnical materials. 
Antifrictional ceramic-metal materials incorporate graphite and other 
components which are carrying out a role of greasing. These materials are used 
for production of sliding bearings plugs applied in automobile, aviation and 
other industries. 
Filters are produced from powders of iron, bronze, nickel, corrosion-resistant 
steel and other materials. They have porosity not less than 50%. 
Ceramic-metal filters are applied to purification of fuel in engines of cars, to 
purification of air and various liquids. 
"Sweating" ceramic-metal materials intend for cooling at the expense of 
coolant evaporation through a time. They are produced from powders of 
corrosion steel, nickel, tungsten, titanium and etc. 
Frictional ceramic-metal materials represent complex compositions on the 
basis of copper and iron. The structure of these materials includes the 
components serving greasing and protecting material from wear (lead, graphite, 
etc.), and also the components giving high frictional properties to a material 
(asbestos, quartz sand, refractory metal connections, etc.). 
Frictional ceramic-metal materials have the increased fragility and low 
durability. Therefore products from them, as a rule, consist of steel basis with 
the layer of frictional metal ceramics put on it. Such materials are applied in 
coupling knots. 
Magnetic ceramic-metal materials are subdivided on: 
- magnetically soft (ferrite) produced from powders of oxides of iron. 
- magnetically hard (constant magnets) ceramic-metal alloys on the basis of the 
iron alloyed by aluminum, nickel, copper, cobalt and subjected to additional heat 
treatment. 
- magnetodielectrics representing compositions of magnetic and insulating 
materials. 
Electrotechnical ceramic-metal materials are produced from a mix of powders 
of refractory metals with copper and silver. Refractory metals define mechanical 
properties of a product, and fusible - serve as a filler and give to materials high 
electric conductance. 
Ceramic-metal electric contacts are applied in magnetic actuators, thermal 
relays and relay of especially heavy mode. 

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Ceramic-metal firm alloys. 
Emergence of ceramic-metal firm alloys was original revolution in processing 
of metals by cutting. Their use allowed to increase cutting speeds at 8-10 time in 
comparison with quick cutting steels. They are received be the method of 
powder metallurgy by agglomeration and pressing of carbides powders of 
refractory metals, such as tungsten, titanium and tantalum with cobalt powder. 
Thus we receive a plate in which carbides are as a basis, and cobalt is as a 
ligament. The plate of the set form are soldered or mechanically fixed to the tool 
case. Heat resistance of firm alloys is 800-900ºС, and hardness and wear 
resistance is much higher, than at quick cutting steels. 
Durability (especially fatigue) of alloys increases with increase in the content 
of cobalt, however their wear resistance thus decreases. In standard brands of 
firm alloys, the content of cobalt fluctuates from 2 to 15%. Durability of firm 
alloys is rather low (three times less, than quick cutting steels). 
Firm alloys with the small content of cobalt possess higher wear resistance, 
but are very fragile. The increase in the content of cobalt to 15% reduces their 
wear resistance to level of quick cutting steels. 
Most often applied firm alloys are divided into three groups: 
1) one-carbide tungsten cobalt alloys TC, 
2) two-carbide tungsten titanium alloys TT, 
3) three-carbide titanium and tungsten tantalum alloys TTT. 
One-carbide tungsten cobalt alloys TC.
These alloys consist of two structural phases: highly rigid carbides of tungsten 
providing to an alloy high hardness and heat resistance, and cobalt reporting to 
an alloy necessary durability. 
Most often applied alloys of TC8, TC6, TC4, TC3, TC2 brands. The figure at a 
letter K designates percentage of cobalt, all the rest - tungsten carbides. The 
alloy TC8 is used for draft, and TC3 and TC2 alloys - for fair processing. 
Properties of alloys can be changed due to technology of their production, for 
example change of size of carbide grain. So, BK6M, BK3M alloys with a fine 
grain possess higher firmness against abrasion, but their durability is slightly 
less in comparison with alloys of TC3 and TC6 brands. The alloy TC8B has 
large grain and therefore it is stronger, but concedes a little to TC8 alloy in wear 
resistance. Alloys of TC are used for processing of cast irons and non-ferrous 
metals, plastic, and also very strong, tempered steel. 
Two-carbide tungsten titanium alloys TT.
Alloys of TT consist of three structural phases: firm solution of carbides of 
tungsten in carbides of titanium - difficult carbide, free carbide of tungsten and 
cobalt. 
Higher cutting properties in comparison with TC alloys get two-carbide alloys 
of TT at the expense of difficult carbide formation. Hardness, heat resistance 
increases, at the same time mechanical durability a little decreases. 

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Most often used alloys are T5K10, T14K8, T15K6, T30K4 brands. Chemical 
composition of these alloys decipher by the following rule: the figure at a letter 
T designates percentage of titanium carbides, at a letter K - cobalt, all the rest - 
tungsten carbides. 
The strongest, but rather less wearproof is T5K10 alloy, the most wearproof, 
but more fragile - T30K4 alloy. Alloys TT have high wear resistance and heat 
resistance therefore they are applied for steel processing. 
Three-carbide titanium and tungsten tantalum alloys TTT.
The specified alloys consist of three phases: firm solution of titanium carbides, 
carbides of tantalum and tungsten carbides - difficult carbide, free carbide of 
tungsten and cobalt. The additive of tantalum increases the fatigue durability of 
an alloy, reduces tendency to a crack formation at cyclic changes of temperature. 
Representatives of these alloys are TT7K12, TT10K8, TT20K9. The chemical 
composition is deciphered so: the figure at letters TT designates total percentage 
of carbides of titanium and tantalum, at a letter K - cobalt, all the rest - tungsten 
carbides. 
TT7K12 alloy are successfully applied at severe conditions of cutting, for 
example when planing steel with big sections of a cut-off layer of metal. The 
alloy of TT10K8 showed by 5-6 times higher firmness at semi-fair and fair 
processing of heat resisting alloys in comparison with T5K10 alloy. 
Mineral ceramic firm alloys. 
The specified alloys represent the polycrystalline body consisting of the 
smallest grains of corundum (Al2O3 aluminum oxide) which size doesn't exceed 
2 mkm, connected by a mineral ligament. 
They are received by the molding under pressure or hot pressing. Possess heat 
resistance to 1200ºС and high hardness. However durability is ten times less, 
than at quick cutting steels. High wear resistance and lack of scarce metals do 
mineral ceramic firm alloys to be very perspective material for cutting tools. 
However low durability limits their application only for fair operations in the 
conditions of very rigid system the machine - tool- detail. 
For increase of cutting properties of mineral ceramics, at agglomeration we 
add carbides of molybdenum, tungsten and titanium. Such materials are called 
cermets. They are a little widespread in production, but with success are applied 
to processing of hardly processed materials.

245 
Fig15. ε–temperature connection with types of
ferrielectric.

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