Aluminium strengthening with carbon?

[krautkramer]

Aluminium strengthening with carbon??

Hi ,

Is it possible to strengthen aluminium with interstitial strengthening by carbon?I couldn't find any aluminium alloy with carbon content.What is the problem behind alloying of carbon with aluminium?

 

[x_engineer]

Carbon is not very soluble in aluminium. In fact, the standard refinement process for aluminium uses carbon electrodes electrolyzing molten alumina, and if it had significant solubility you would not be able to use this process.

I guess you could try ion implantation - but that would be a very expensive process!

 

[Astronuc]

Al and C do not form a thermodynamically stable compound.

See - Aluminum and Aluminum Alloys
http://www.keytometals.com/page.aspx?ID=CheckArticle&site=ktn&NM=2

Aluminum Alloys – Effects of Alloying Elements
http://www.keytometals.com/page.aspx?ID=CheckArticle&site=ktn&NM=55

Carbon may occur infrequently as an impurity in aluminum in the form of oxycarbides and carbides, of which the most common is Al₄C₃, but carbide formation with other impurities such as titanium is possible. Al₄C₃ decomposes in the presence of water and water vapor, and this may lead to surface pitting.

See also - http://www.keytometals.com/page.aspx?ID=Articles&LN=EN
The Basics of Nonferrous Metallurgy

Aluminum - Lithium Alloys
High Strength Aluminum P/M Alloys
Resistance to Fracture of AlZnMgCu (AA7000) High Strength Aluminum Alloys
Surface Treatment Of Aluminum And Aluminum Alloys
Aluminum – Copper Alloys
Aluminum-Magnesium-Silicon (6000) Alloys
Aluminum-Magnesium (5000) Alloys
Aluminum-Zinc-Magnesium Alloys
Aluminum–Silicon Alloys
Aluminum and Aluminum Alloys Casting Problems
Sintered Aluminum Powder (SAP)
High Strength Aluminum P/M Alloys
How Deformation Affects the Mechanical Properties of Aluminum Forgings
Metallurgical Factors Affecting High Strength Aluminum Alloy Production
Aluminum Alloy 7075: The Relation between Microstructure and Toughness
The Effect of Ingot Processing on Fatigue Properties of 7475-T6 Plates
Rapidly Solidified Aluminum Alloys
Hot Forming of Al-Mg Alloy Sheet
The Influence of Microstructure on High Temperature Properties of 2024 Alloy
Work Hardening Aluminum Alloys: Part One
Work Hardening Aluminum Alloys: Part Two
Microalloying of Advanced Al-Zn-Mg-Cu Alloy
Ballistic Protection Efficiency of Aluminum Alloys
Melting and Alloying Aluminum Alloys
Formability Tests of 2036-T4 Aluminum Alloy: Part One

 

[mikegem]

Al and C do not form a thermodynamically stable compound.

I think it does. Please see http://en.wikipedia.org/wiki/Aluminium_carbide

The formation of aluminum carbide suggests why carbon nanotubes (probably the MWNT types) might be a superior reinforcing fiber for aluminum due to the potential for high interface strength between the fibers and the aluminum matrix.

 

[Astronuc]

I think it does. Please see http://en.wikipedia.org/wiki/Aluminium_carbide

The formation of aluminum carbide suggests why carbon nanotubes (probably the MWNT types) might be a superior reinforcing fiber for aluminum due to the potential for high interface strength between the fibers and the aluminum matrix.

Perhaps I am using the wrong terminology, but I was thinking about the fact that "Aluminium carbide hydrolyses with evolution of methane. The reaction proceeds at room temperature but is rapidly accelerated by heating." [from the Wikipedia article] Perhaps chemically unstable in the presence of water is a better statement.

 

[mikegem]

Aluminum carbide is a thermodynamically stable compound in that it occupies a lower energy level than the aluminum and carbon reactants from which it forms, or the reaction would not proceed.

Aluminum carbide is a thermodynamically unstable compound with respect to the potential reaction products when exposed to water. As is aluminum itself unstable with respect to atmospheric oxygen under normal ambient temperature, with the metal's apparent stability owing to the immediate formation of a thin, protective oxide layer that terminates the oxidation reaction.

I took the sense of your statement to mean that aluminum could not form a carbide. It clearly does, and the compound shows no tendency to spontaneously decompose. Thus with regard to the OP's original question about alloying aluminum with carbon, I think it is accurate to say (1) aluminum can form a persistent carbide and (2) that compound would be stable intermixed with aluminum.