Light metals · Workhorse

Aluminum 6061 / 6063 / 5083

Al 6063values describe: 6063 extruded

Big science (accelerators, light sources, public fusion)Semiconductor equipment & lithographyChipmakers (foundries & IDMs)Space test

Why it wins

Extrudable into kilometers of complex antechamber profile, low bulk hydrogen, high conductivity spreads photon heat, non-magnetic, machines fast. The chamber metal of light sources and semiconductor process tools.

Why not the alternative

Stainless cannot be extruded and stores far more hydrogen, but aluminum caps bakeout near 150 to 200 C and needs special welding or bimetal CF transitions.

Watch out

Thick porous anodizing traps water; threads gall.

Properties

The values below are candidate: compiled from the sources named, not yet individually validated. Provisional provenance: CERN vacuum group compilations and coating programme; O'Hanlon, A User's Guide to Vacuum Technology; ASM Handbook: properties, corrosion, heat treatment.

Wet cleaning

Recipe	mild alkaline or neutral detergent, DI rinse, hot dry; extrude under argon to keep the oxide thin
Forbidden	sodium hydroxide attacks the metal; never anodise a UHV surface
Limit	the hydrated oxide is the gas source: a thin oxide beats a clean one

Vacuum and outgassing

Outgassing, unbaked (10 h)	8e-9 mbar·L/s/cm²
Outgassing, baked	1e-11 mbar·L/s/cm²
Vapour pressure	negligible below 400 °C

Temperature

Bake, assembled	200 °C
Vacuum degas	300 °C
Braze / H2 firing	not-applicable
Metallurgical limit	T6 temper lost above 200 °C

Thermal

CTE	23.6 ppm/K
Thermal conductivity	167 W/m·K
Specific heat	896 J/kg·K
Emissivity	0.04–0.06 bare, 0.8 anodised
Melting / softening	582–652 °C

Mechanical

Strength	276 ys (6061-T6) MPa
Tensile	310 MPa
Elongation	12 %
Young's modulus	68.9 GPa
Hardness	95–107 HV
Density	2.7 g/cm3

Electrical and magnetic

Relative permeability	1.000022
Resistivity	4 µΩ·cm

Engineering

Corrosion	good, self-passivating
Joining	TIG and friction stir; brazing is difficult
Process notes	vacuum extrusion beats machining for outgassing
Availability and cost	the cheapest structural metal in stock

Brazing

Sourced pairings

With	Filler	Atmosphere	Expansion gap at set
Aluminum 6061 / 6063 / 5083	BAlSi-2	vacuum furnace	expansion absent on both sides. Side A, 577 °C is outside the range of aluminum-6061 (20 to 300 °C), never extrapolated. Side B, 577 °C is outside the range of aluminum-6061 (20 to 300 °C), never extrapolated

Compatibility

What documents state about this material faced with a filler metal, without the other member of the joint. A statement that names the exact filler comes first. A statement about a whole AWS class comes after it: a class covers dozens of alloys, so it is the weaker of the two, and the corpus never turns one into the other. Last come statements about a pair of base metals that name no filler at all. They are the weakest of the three, and they do not contradict the two above: a table that cannot generalize about a pair can still list a filler class for each metal of that pair separately. The three levels answer three different questions.

listedAWS class BAlSi
The AWS combination table lists the BAlSi class for brazing this base metal to Al and Al alloys, stainless steel, Ni and Ni alloys, Ti and Ti alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cells that carry this class for this base metal name these partners: Al and Al alloys, stainless steel, Ni and Ni alloys, Ti and Ti alloys. A partner is what the cell pairs the base metal with, it does not index this entry. The table lists classes, it does not qualify them, and an empty cell is never a prohibition. The class is written as the document writes it, BAl-Si becoming BAlSi here, and it is never mapped to any grade of the corpus. The number sign printed by the document on this cell reads: recommended only if the nonaluminum alloy is nickel plated first. The table names the family Al and Al alloys. The corpus carries 6061 under aluminum-6061, so the entry is narrower than the cell it records.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.

Against another base metal, no filler named:

no generalizationBeryllium
The AWS combination table states that no generalization can be made about brazing this base metal to Al and Al Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: Y means generalizations on these combinations cannot be made, refer to appropriate individual chapters for usable filler metals. The document names this family Be, Zr, V, and alloys reactive metals and enumerates three metals of which the corpus carries only beryllium, so the entry names one member of a group the document treats together. The row label of the same family is printed without the comma after Zr. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedCarbon and Low-Alloy Steels
The AWS combination table does not recommend brazing this base metal to Carbon and Low-Alloy Steels.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The number sign printed by the document on this cell reads: recommended only if the nonaluminum alloy is nickel plated first. The document therefore prints a refusal and a condition under which the joint becomes possible, and the corpus carries both. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedCast Iron
The AWS combination table does not recommend brazing this base metal to Cast Iron.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedMg and Mg Alloys
The AWS combination table does not recommend brazing this base metal to Mg and Mg Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedMolybdenum and TZM
The AWS combination table does not recommend brazing this base metal to Al and Al Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The document names this family W, Mo, Ta, Nb, and alloys refractory metals and enumerates its four metals itself, so the corpus writes the cell under each of the four it carries. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedNiobium RRR 300
The AWS combination table does not recommend brazing this base metal to Al and Al Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The document names this family W, Mo, Ta, Nb, and alloys refractory metals and enumerates its four metals itself, so the corpus writes the cell under each of the four it carries. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedOxygen-free copper C10100 / C10200
The AWS combination table does not recommend brazing this base metal to Al and Al Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The table names the family Cu and Cu Alloys, and the corpus carries only oxygen-free copper C10100 and C10200 under copper-ofe. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedTantalum
The AWS combination table does not recommend brazing this base metal to Al and Al Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The document names this family W, Mo, Ta, Nb, and alloys refractory metals and enumerates its four metals itself, so the corpus writes the cell under each of the four it carries. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedTool Steels
The AWS combination table does not recommend brazing this base metal to Tool Steels.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.
not recommendedTungsten
The AWS combination table does not recommend brazing this base metal to Al and Al Alloys.
Conditions and source
Book page 75, chapter 3, table 3.2, Base Metal-Brazing Filler Metal Combinations. The cell names no filler metal of any kind, neither a grade nor an AWS class. It states something about the combination of two base metals and nothing else. The document prints this reserve under the table and it is carried here in full: X means not recommended, however special techniques may be viable for certain dissimilar metal combinations. The document names this family W, Mo, Ta, Nb, and alloys refractory metals and enumerates its four metals itself, so the corpus writes the cell under each of the four it carries. The table names the family Al and Al Alloys, and the corpus carries 6061.
[A]AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment
Handbook of the American Welding Society. Three tables are read by the corpus. Table 3.2 page 75, Base Metal-Brazing Filler Metal Combinations, a two-entry matrix of base metal families whose cells carry AWS filler classes. Table 3.3 page 76, Maximum Service Temperatures Recommended for Various Brazing Filler Metal Compositions, one continuous and one short-term temperature per class. Table 33.1 page 585, Composition of Brazing Filler Metals Specially Produced for the Brazing of Vacuum Devices and Equipment, with liquidus and solidus in Fahrenheit and Celsius. The chapter, the table and the page of each statement are carried by the entry that uses it, never by this registry line.

Chemical affinity

What documents state about a BINARY SYSTEM, one element of a filler metal faced with one element of this material. An affinity is not a verdict on a joint: a joint brings many binaries together at once, some helpful and some harmful, and what follows is the list of those the corpus can name. The count below is not written anywhere. It falls out of the crossing of this material's elements with the composition of every filler the corpus holds, so it grows on its own the day a binary enters the corpus.

Elements of this material: Al, from the compositional designation.

dissolution and erosion3 fillersSi against Al1 source+1 statement

The molten filler dissolves the base, or the base dissolves into the filler far enough to change what the filler is. The joint loses base metal, or the filler stops flowing.

Silicon from the filler penetrates an aluminium base, lowers its melting point, and lets the molten braze penetrate the substrate. The result is erosion of the base, and long wetting times are what bring it on.Si against Al

3 fillers: 4047, BAlSi-2, BNi-2

Conditions and verbatim

Book page 137, conclusions of a study on brazing aluminium matrix composites. The chapter states that long wetting times aid silicon penetration in the base matrix and the reduction of its melting point and can lead to the penetration of molten braze into the substrate, resulting in erosion, and that the problem is less significant for the 7005-matrix composite and can be reduced if shorter wetting times are used. The body of that study is a METAL MATRIX COMPOSITE, 6061 or 7005 reinforced with alumina, and not the wrought alloy this corpus carries under aluminum-6061. The reinforcement is what the same conclusions blame for the loss of wetting and spreading, while the silicon penetration they describe is a phenomenon of the aluminium matrix. The temperature carried is the upper bound of the optimal wetting window the study determines for the 6061-matrix composite, 580 to 590 C, and it is a wetting optimum rather than a threshold of the mechanism.

Characteristic temperature590 °C, M. M. Schwartz, Brazing, 2nd edition, ASM International, 2003, chapter 4, Base Metals and Base-Metal Family Groups, DOI 10.1361/brse2003p063

Source[A] M. M. Schwartz, Brazing, 2nd edition, ASM International, 2003, chapter 4, Base Metals and Base-Metal Family Groups, DOI 10.1361/brse2003p063

Source conditionsChapter 4 of the second edition, book pages 63 to 162 in the copy read, which treats base metals family by family and states metallurgical reactions, atmosphere limits and filler selection guides. It is a handbook chapter, not a qualification record. The page of each statement is carried by the entry that uses it, never by this registry line.

Open in the brazing abacus →

Outgassing

12 sourced measurements for this card, 1 prescribed condition or published threshold. A rate means nothing without the pumping time it was read at, so each one states it or declares it missing. The whole base, filters included, is at /tools/outgassing/.

Signature: 1e-8 unbaked to 1e-13 baked, a drop of 5.5 decades.

Sourced outgassing measurements for this card
Material as published	Species	State	Pumping time	Rate
6061-T651 aluminum, no heat treatment	H2	baked	not applicable, the source states the rate independent of pumping time	5.50e-14mbar·L/s/cm²
Al alloys	H2	baked	not applicable, the source states the rate independent of pumping time	about1.00e-13mbar·L/s/cm²
AA 6060 Al alloys	H2	baked	not applicable, the source states the rate independent of pumping time	at most1.00e-13mbar·L/s/cm²
6061-T651 aluminum, no heat treatment	H2O	unbaked	the abscissa of the curve below	1.60e-8 at 0.556 h to 3.00e-10 at 27.778 h
Aluminium and aluminium alloys, 2000, 4000, 5000 and 6000 series, wrought form	total	unbaked	NOT STATED by the source	1.01e-8mbar·L/s/cm²
Aluminium (fresh)	total	unbaked	the abscissa of the curve below	8.40e-9 at 1 h to 8.00e-10 at 10 h
Aluminium (degassed 24 h)	total	unbaked	the abscissa of the curve below	5.52e-9 at 1 h to 4.08e-10 at 10 h
Aluminium (3 h in air)	total	unbaked	the abscissa of the curve below	8.87e-9 at 1 h to 6.33e-10 at 10 h
Aluminium (fresh)	total	unbaked	the abscissa of the curve below	8.27e-9 at 1 h to 4.33e-10 at 10 h
Aluminium (bright rolled)	total	unbaked	10 h	1.00e-8mbar·L/s/cm²
Aluminium	total	baked	NOT STATED by the source	5.33e-13mbar·L/s/cm²
Aluminium	total	baked	NOT STATED by the source	5.33e-14mbar·L/s/cm²

Prescribed, not measured

procedure, Aluminium 6061-T6. Bake 150 C, 48 h, vacuum.

Sources: S-FEDCHAK-2021, S-CHIGGIATO-CAS-2017, S-LIGO-E960050-V13, S-LIGO-E960022-V24, S-ELSEY-1975-II. Full citations and conditions at the base and in /data/outgassing.json.

Grades

6061-T6	machined chamber bodies and general structure; weldable, loses temper at welds
6063-T5	the extrusion grade: light source antechamber profiles by the kilometer
5083-O	large welded chambers and cryo: weld-friendly, no temper to lose
2219	aerospace tanks and high strength at temperature
7075	avoid in baked vacuum: 5.6 percent Zn, poor weldability; mechanics only, cold, coated

Sources · 1

NEG development for MAX IV vacuum system

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