For example
If we add 30wt.% Cr, 5wt.% tungsten (W), 2wt% Ni and rest is Cobalt. so after casting what is called as :
1) Is it an alloy..? or
2) is it an metal matrix alloy composite..?
Alloy is a combination of solute and solvent in both liquid and solid state.
Composite has got 2 distinct phases, a matrix phase and a reinforcement phase in which the reinforcement phase is an insoluble one.
Alloys are conventional materials.
Composites are reinforced materials, otherwise called as TAILORED MATERIALS to enhance the properties.
Dear Amit,
The alloy is solid solution of two or more constituent where physical significance of each constituent is not generally possible but each constituent has effect on overall properties (ex: tea, coffee etc). Composite is material with two or more constituent where physical significant of each is clearly possible but each constituent has effect on overall properties of material (ex: poha, sabjee etc).
For your specific case, it is quite difficult to state where its is composite or alloy. I will try to describe the issue from which you need to make judgement for your case. The main criteria for this is the temperature up to which you heated the mixture. If temperature in your case is above melting point of all the constituent then its alloy othewise its composite.
(Note please: The answer quoted by me is purely personal and possibility of disagreement with somebody)
Actually, an alloys doesn´t need to be a solid solution.
I would consider a composite if the different phase present in the material are not a result of preciptation or in situ reaction.
Some may say that composite is when there are presence of materials from different classes (Metal, ceramic, polymer...), which is not completely right if you have in mind the CMCs (ceramic matrix composites) such as alumina fibers in an alumina matrix.
If the constituents remain as such even after solidification and cooling to room temperature, the produced material can be called as composite. Usually metal particles either dissolve or react among them to produce solid solution or intermetallics during casting operation. Even after reaction if any such intermetallic particle remain in phase equilibrium, this can still be considered as composite. For example Al/Al3Ti composite. In your case, there exists a clear phase diagram between Co and Cr. Please refer the below link. The material produces Cobalt-rich hexagonal close-packed (HCP) phase upon cooling if Cr is added greater than 20 wt.%. Hence, the resultant material is still an alloy.
http://www.calphad.com/cobalt-chromium.html
Amit, as it was mentioned earlier, it depends on the temperature at which the combination was carried out. If the temperature was above those of the additive metals' melting point, then your product is an alloy. But if the combination temperature is just at melting point of the matrix material, Cobalt and the reinforcements were not melted, then the product is a composite. Thus, in alloy formation all the components were melted and then combined together while composite only the matrix material or the basement element need to be melted before the combination. The reinforcements in composite are added as dispersed particles.
Just my little understanding and I stand to be corrected, thank you!
PhD student of Analytical Environmental Chemistry
Alloy is a combination of solute and solvent in both liquid and solid state.
Composite has got 2 distinct phases, a matrix phase and a reinforcement phase in which the reinforcement phase is an insoluble one.
Alloys are conventional materials.
Composites are reinforced materials, otherwise called as TAILORED MATERIALS to enhance the properties.
The main constituents of the composites are the base material (matrix phase) and the filler material (reinforcement phase) e.g. metal matrix composites and polymer matrix composites. The matrix holds the filler material in a favorable orientation within the composite to show the best combination of their properties. The properties of composites can be tailored by varying reinforcement ratio.
However, An alloy is a solid solution of metal elements or a mixture of metallic phases e.g. brass and steel.
In alloy the two or more materials are soluble in each other like in alloys or you can say if you solidify salt in water mixture...in composites two or more materials are not soluble in each other like if you solidify sand in water mixture....in this one or more reinforced materials are suspended or mixed in a matrix to improve properties...in this two soluble materials are also mixed some times but one is at solid state or one at melted state and then solidified
Dear Sir, alloy is a homogeneous solid solution. Whereas, composite materials (metallic), are heterogeneous mixture of all the said constituents. Hence, they tend to have only mixed performance.
Alloys makes the solid solution with the alloying elements at an elevated temperature but composite do not make the solid solution here the phases remains distinct.
Alloy is the combination of two or more elements that are soluble in the base alloy. However composite are those where the reinforcing phase not soluble in base matrix. This is the first basic difference between the alloy and composite.
In composites, the presence of metal form in composition is not mandatory but alloys needs at least one metal form. So for a key difference, we can say that alloys are metallic whereas composites can be metallic as well as non metallic in nature.
Alloy is the combination of two or more materials (mostly metallic like iron, copper, aluminium and magnesium as well as few non-metallic like carbon, sulfur and oxygen) which are soluble to each other and form solid solution at certain temperature. In alloy, the alloying elements are mixed together in the atomic level and are not separated by any boundary.
Composite is the combination of two or more different materials which are physically distinct by certain boundary. Here two material are not soluble to each other. The main objective of composite is to achieve the properties of both matrix as well as reinforcement. In composites both the phase are separated by the interface.
In your case ( 30 wt.% Cr, 5 wt.% tungsten (W), 2 wt% Ni and rest is Cobalt ) if you able to hold the material at the certain temperature (as per phase diagram) then it will form alloy else will form composites. Good quality of composite also may not be produced by this composition, because the composition of chromium and other material is more then 30 %, so it will agglomerate.
Hi
The main difference between alloy and composite is their composition. An alloy has at least one metal in its composition while composites don't have any metal components.
Hello
Composites are made from two or more separate materials bonded in such a way as to form one solid piece of material. i.e. steel rods in a concrete matrix
Alloys are mixtures of primarily metal atoms which form a continuous solid solution. i.e. steel, a mixture of iron and carbon
Hello
1- Alloy is a homogenous or a heterogeneous mixture whereas composites are heterogeneous.
2- There is at least one metal in alloy, but it is not necessary to have metals in composites.
Hello.
Actually, in the alloy just limited on a specific metal whereas in the composites multi material and metals will be used.
Good luck
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