Metal Alloy and Viscosity
Metal Alloy and Viscosity
(OP)
Hi,
I have a question regarding a Metal alloys and their viscosity.
I know that pure metals go from solid into liquid without a 'glass state' when heated. (not like thermoplastic for example, which goes from solid into plastic state when heated).
Does metal alloys behave differently? are there metal alloys that when heated to a specific temperature reach to a 'plastic like' state, for example - like honey or peanut butter
?
Will appreciate your thoughts on this matter.
I have a question regarding a Metal alloys and their viscosity.
I know that pure metals go from solid into liquid without a 'glass state' when heated. (not like thermoplastic for example, which goes from solid into plastic state when heated).
Does metal alloys behave differently? are there metal alloys that when heated to a specific temperature reach to a 'plastic like' state, for example - like honey or peanut butter
?Will appreciate your thoughts on this matter.





RE: Metal Alloy and Viscosity
So over a range of 100-300C there is a slush, a mixture of solid and liquid.
And the composition is changing over the range. These mixtures are sometimes thixotropic.
This is used is some cases (such as with Mg) to allow injection molding in the slush state.
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P.E. Metallurgy, Plymouth Tube
RE: Metal Alloy and Viscosity
Are there rheopectic metal alloys?
RE: Metal Alloy and Viscosity
RE: Metal Alloy and Viscosity
RE: Metal Alloy and Viscosity
Erangir, can you please explain your interest in rheopectic phenomenon. As metallurgists we are concerned about increase in viscosity ( loss of fluidity) with decrease in temperature. Physicists might have a different approach.
I finally hope this is not a student question.
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
RE: Metal Alloy and Viscosity
As EdStainless noted there are semi-solid casting processes that take advantage of some non-ferrous metals in the condition you describe to produce parts with very fine detail.
https://en.wikipedia.org/wiki/Semi-solid_metal_cas...
Friction/stir welding use friction heat and relative motion at the weld interface to create a metallurgical bond with the materials in a plastic state. These are considered solid state joining processes, since the metal does not experience a phase change between solid & liquid like fusion welding processes. Stir welding is mostly limited to light alloys like aluminum. Friction welding can be performed with almost any metal alloy.
RE: Metal Alloy and Viscosity
This is on top of the changes in viscosity with temperature once you are fully liquid.
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P.E. Metallurgy, Plymouth Tube
RE: Metal Alloy and Viscosity
Perhaps if you look for information under " Semi Solid Processing", it will help.
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
RE: Metal Alloy and Viscosity
My interest in the rheopectic phenomenon is the ability to be to 3D print metal in it molten state.
A few people tried to do this and discussed this.
Thermoplastic have a very good viscosity controlled zone. I'm afraid that when I'll try to print a metal alloy, since it's half liquid-half solid, the output won't be smooth as with polymer 3d printing.
Look also at this.
And no, it's not a student question :)
RE: Metal Alloy and Viscosity
Maybe, you have to adopt a 2 stage process, first cast them using 3D printing technology and then to further improve the integrity of the casting, use squeeze casting technique. I am no expert , perhaps you may contact Prof Thiel in Northern Iowa Univ, who have recently added 3d moulding facility.
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
RE: Metal Alloy and Viscosity
Here's my suggestion for a 3D metal component manufacturing that I've never seen anyone do. Remember the early type of 3D prototype machines that made parts from stacked layers of laser cut paper plies? If you need a 3D component made of very high quality metal, why not use the same process with thin plies of cold rolled, vacuum melt materials. After trimming and stacking the metal plies, they could be consolidated by HIP-ing.
RE: Metal Alloy and Viscosity
https://www.youtube.com/watch?v=5s0J-7W4i6s
RE: Metal Alloy and Viscosity
RE: Metal Alloy and Viscosity
This is true except for eutectic alloys that melt at a specific temperature so there is no slush or plastic temperature zone for these alloys.
Design for RELIABILITY, manufacturability, and maintainability
RE: Metal Alloy and Viscosity
Maui