Precious Metal BVAu-7
UNS P00507
BVAu-7 is a vacuum-service gold-copper braze filler at roughly 50%Au-50%Cu (UNS P00507) with controlled volatile impurity content for use in vacuum-tight assemblies.
Reference datasheet — BVAu-7 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
BVAu-7 tempers and conditions
BVAu-7 is supplied in one standard condition, AS-BRAZED.
Supply forms, finishes and certifications
Ways BVAu-7 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOIL | Foil / ribbon, rolled and annealed | Supply form |
POWDER-PASTE | Atomised powder / binder paste | Supply form |
PREFORM | Stamped preform | Supply form |
Wire-AnnDefault | Wire, annealed | Supply form |
WIRE-HD | Wire, cold drawn | Supply form |
What is BVAu-7?
BVAu-7 is a vacuum-service gold-copper braze filler at roughly 50%Au-50%Cu (UNS P00507) with controlled volatile impurity content for use in vacuum-tight assemblies. It gives a cost-reduced vacuum-grade Au-Cu option where the joint temperature range permits, and is supplied as annealed or hard-drawn wire, foil, preforms, powder and paste. Typical values are 200 MPa yield, 420 MPa tensile, 25% elongation and a formability rating of 85. Slow cooling promotes AuCu3 ordering and hardening; where higher gold content and greater vacuum margin are needed, BVAu-2 is the alternative. BVAu-7 has a density of 12.2 g/cm³ (0.441 lb/in³), heavier than 69% of precious metal grades. It melts at 970°C (1,778 °F). BVAu-7 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 51% of precious metal grades. Elongation at break is 25% and the elastic modulus is 95 GPa (13.8 Msi).
What is BVAu-7 used for?
- Vacuum electronic device brazing
- Aerospace vacuum-tight joints
- Precision instrument assemblies
- Hermetic feedthroughs
BVAu-7 properties
Typical room-temperature values; bars are the position among precious metal grades.
Physical3
BVAu-7 has a density of 12.2 g/cm³ (0.441 lb/in³), heavier than 69% of precious metal grades. It melts at 970°C (1,778 °F).
Mechanical9
BVAu-7 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 51% of precious metal grades. Elongation at break is 25% and the elastic modulus is 95 GPa (13.8 Msi).
Thermal6
BVAu-7 is rated for continuous service to 425°C (797 °F). It conducts heat at 65 W/m·K (37.6 BTU/hr·ft·°F), worse than 67% of precious metal grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
BVAu-7 conducts electricity at 15 % IACS, worse than 65% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (76/100), worse than 59% of precious metal grades.
Sustainability4
Producing a kilogram of BVAu-7 takes about 130,000 MJ of energy and emits 9,000 kg of CO₂ — more than 70% of precious metal grades. Typical recycled content is 55%.
Manufacturability6
BVAu-7's machinability is fair (35/100, worse than 73% of precious metal grades); weldability poor (30/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the precious metal family
Yield strength against density for every precious metal grade FabDigit runs. BVAu-7 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BVAu-7
Is BVAu-7 easy to machine?
Rarely machined; the alloy is soft and gummy — use sharp, polished-flute carbide tools, light feeds and collect all swarf for precious-metal recovery.
Can BVAu-7 be welded?
Not a structural weld consumable; join by vacuum or dry-hydrogen furnace brazing at about 1000–1050 °C with tight 25–75 µm gaps and no flux.
Can BVAu-7 be formed, bent or molded?
Readily cold drawn to fine wire and rolled to foil with interstage anneals at 600–700 °C in protective atmosphere; slow cooling promotes AuCu3 ordering and hardening.
BVAu-7 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Auvacuum-grade purity, refined bullion feedstock | 49.5 – 50.5 | 50 |
| Znhigh-vapour-pressure element, restricted for vacuum service | ≤ 0 | |
| Cdhigh-vapour-pressure element, restricted | ≤ 0 | |
| Prestricted to avoid brittle phosphides | ≤ 0 | |
| Pbvolatile impurity limit | ≤ 0 | |
| Cresidual from processing | ≤ 0.01 | |
| Other elements, totalsum of unspecified residuals per vacuum-grade practice | ≤ 0.15 | |
| Cuoxygen-free / vacuum-refined copper | balance |
What surface finishes work on BVAu-7?
As-brazed fillets are bright and need no post-clean; can be lightly polished or ultrasonically cleaned, and plating is unnecessary since the alloy does not scale.
Equivalent designations
Standards and trade names that resolve to Precious Metal BVAu-7 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P00507
- Also called
- AWS BVAu-7
How much does BVAu-7 cost?
BVAu-7 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
BVAu-7 — frequently asked
What is BVAu-7 used for?
BVAu-7 is typically used for vacuum electronic device brazing, aerospace vacuum-tight joints, precision instrument assemblies and hermetic feedthroughs. In short: lowest-cost vacuum Au braze; half-gold Au-Cu filler; tight-clearance vacuum joints.
What is the yield strength of BVAu-7?
BVAu-7 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 51% of precious metal grades.
Is BVAu-7 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 73% of precious metal grades). Rarely machined; the alloy is soft and gummy — use sharp, polished-flute carbide tools, light feeds and collect all swarf for precious-metal recovery.
Can BVAu-7 be welded?
Not readily — weldability is rated poor (30/100). Not a structural weld consumable; join by vacuum or dry-hydrogen furnace brazing at about 1000–1050 °C with tight 25–75 µm gaps and no flux.
What surface finishes work on BVAu-7?
As-brazed fillets are bright and need no post-clean; can be lightly polished or ultrasonically cleaned, and plating is unnecessary since the alloy does not scale.
Can BVAu-7 be formed, bent or molded?
Readily cold drawn to fine wire and rolled to foil with interstage anneals at 600–700 °C in protective atmosphere; slow cooling promotes AuCu3 ordering and hardening.
What is the maximum service temperature of BVAu-7?
BVAu-7 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BVAu-7 cost?
BVAu-7 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AWS A5.8M/A5.8 Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- Brazing Handbook, 5th Edition — American Welding Society (2007)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol.2 — Properties of Nonferrous Alloys (precious metals) — ASM International (1990)
- Gold-copper vacuum brazing filler metals (wire, foil, preforms) — Morgan Advanced Materials / Wesgo Metals (2022)
- GB/T 18762 (precious metal brazing filler metals) — SAC (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.