Aluminum B4C/6061-T651
Temper · default condition
also MMCC B4C-Al
T651 = t6, stress relieved by stretching
Standard stocked condition for flat neutron-absorber plate that will be machined to close tolerance without distortion.
Values for the T651 condition
Other B4C/6061 tempers and conditions
B4C/6061 is listed in 10 conditions; see the grade overview at B4C/6061.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose when the panel must be bent, roll-formed or deep-drawn before final ageing. | 85 | 165 | 12 | 48 HB | 38 % IACS |
As fabricated | Lowest-cost condition for non-structural shielding plate where strength is not credited. | 150 | 250 | 8 | 75 HB | 36 % IACS |
Solution heat treated and naturally aged | Intermediate strength with better ductility for forming operations after solution treatment. | 175 | 285 | 9 | 85 HB | 28 % IACS |
Solution heat treated and overaged (stabilized) | Pick for cask baskets that see long-term elevated temperature, to lock dimensions and avoid in-service ageing drift. | 245 | 290 | 6 | 95 HB | 36 % IACS |
Cooled from hot working and artificially aged | Economical temper for extruded absorber channels and angles where full T6 strength is not required. | 255 | 300 | 5 | 100 HB | 33 % IACS |
30 vol% B₄C | Maximum practical loading for thin, high-¹⁰B-density shielding sheet; brittle, PCD tooling and abrasive waterjet cutting mandatory. | 270 | 290 | 1.5 | 148 HB | 24 % IACS |
20 vol% B₄C | Common rack-panel loading giving high ¹⁰B areal density in thin plate with acceptable handling strength. | 295 | 330 | 3 | 128 HB | 29 % IACS |
T651DefaultThis page T6, stress relieved by stretching | Standard stocked condition for flat neutron-absorber plate that will be machined to close tolerance without distortion. | 300 | 345 | 4.5 | 115 HB | 32 % IACS |
Solution heat treated and artificially aged | Peak-strength condition for extrusions, forgings and machined absorber components. | 300 | 345 | 4.5 | 115 HB | 32 % IACS |
10 vol% B₄C | Lowest loading: best ductility and machinability, for thicker sections where areal ¹⁰B density is made up by thickness. | 305 | 350 | 6 | 105 HB | 35 % IACS |
What is B4C/6061-T651?
B4C/6061-T651 is B4C/6061 in the T651 temper — standard stocked condition for flat neutron-absorber plate that will be machined to close tolerance without distortion. B4C/6061-T651 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 77% of aluminum grades. Elongation at break is 4.5% and the elastic modulus is 92 GPa (13.3 Msi). B4C/6061-T651 has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 582°C (1,080 °F).
Advantages
- Stiff — 92 GPa (13.3 Msi), better than 99% of aluminum grades
- High service temperature — 175°C (347 °F), better than 83% of aluminum grades
- High strength — 300 MPa (43.5 ksi), better than 77% of aluminum grades
Limitations
- Difficult to machine — 22/100, worse than 98% of aluminum grades
- High embodied carbon — 14 kg CO₂/kg, worse than 95% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
- Difficult to weld — 25/100, worse than 76% of aluminum grades
B4C/6061-T651 properties
Typical room-temperature values for B4C/6061-T651; 11 are specific to this condition. Other listed values are B4C/6061 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
B4C/6061-T651 has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 582°C (1,080 °F).
Mechanical15
B4C/6061-T651 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 77% of aluminum grades. Elongation at break is 4.5% and the elastic modulus is 92 GPa (13.3 Msi).
Thermal6
B4C/6061-T651 is rated for continuous service to 175°C (347 °F). It conducts heat at 140 W/m·K (80.9 BTU/hr·ft·°F), worse than 52% of aluminum grades. Thermal expansion is 20.5 µm/m·K (11.4 µin/in·°F).
Electrical3
B4C/6061-T651 conducts electricity at 32 % IACS, worse than 63% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of B4C/6061-T651 takes about 235 MJ of energy and emits 14 kg of CO₂ — more than 97% of aluminum grades. Typical recycled content is 5%.
Manufacturability8
B4C/6061-T651's machinability is poor (22/100, worse than 98% of aluminum grades); weldability poor (25/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with B4C/6061-T651
Is B4C/6061 easy to machine?
Highly abrasive — use PCD or CVD-diamond tooling, high speed/low feed, flood coolant; abrasive waterjet or diamond sawing for cut-to-size, and expect carbide tools to fail in minutes.
Can B4C/6061 be welded?
Friction stir welding and solid-state joining are preferred; fusion (TIG/MIG) with 4043/4047 filler is possible only in low-loading grades because molten Al reacts with B₄C to form brittle Al₃BC/AlB₂ and the weld pool is sluggish — mechanical fastening is common in racks.
Can B4C/6061 be formed, bent or molded?
Supplied by powder metallurgy consolidation plus extrusion/rolling; cold forming limited to gentle bends (≥4t radius) in O or T4 temper, hot forming 400–480 °C for tighter radii.
What surface finishes work on B4C/6061?
Sulfuric or hard anodize gives an uneven film because B₄C particles do not convert; chromate/trivalent conversion coating or paint is the usual protection, and mechanical polishing leaves particle relief.
B4C/6061 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 |
|---|---|---|
| B4C (particulate reinforcement)wt%; 15 vol% ≈ 14 wt%. Enriched ¹⁰B optional; natural B is ~19.9 % ¹⁰B | 9 – 30 | 14 |
| Mgmatrix (6061) | 0.8 – 1.2 | 1 |
| Simatrix (6061) | 0.4 – 0.8 | 0.6 |
| Cumatrix (6061) | 0.15 – 0.4 | 0.28 |
| Crmatrix (6061) | 0.04 – 0.35 | 0.2 |
| Feimpurity max | ≤ 0.7 | 0.3 |
| Mnimpurity max | ≤ 0.15 | — |
| Znimpurity max | ≤ 0.25 | — |
| Tiimpurity max | ≤ 0.15 | — |
| Others (each/total)0.05 each / 0.15 total | ≤ 0.15 | — |
| Almatrix balance | balance | — |
B4C/6061-T651 — frequently asked
What is B4C/6061-T651 used for?
B4C/6061-T651 is typically used for spent nuclear fuel racks, neutron shielding panels, cask liners and radiation shielding structures. In short: neutron-absorbing aluminum MMC; lightweight shielding structural plate; requires diamond tooling.
What is the yield strength of B4C/6061-T651?
B4C/6061-T651 has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 77% of aluminum grades. Strength varies by condition: see the 10 listed tempers.
Is B4C/6061-T651 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 98% of aluminum grades). Highly abrasive — use PCD or CVD-diamond tooling, high speed/low feed, flood coolant; abrasive waterjet or diamond sawing for cut-to-size, and expect carbide tools to fail in minutes.
Can B4C/6061-T651 be welded?
Not readily — weldability is rated poor (25/100). Friction stir welding and solid-state joining are preferred; fusion (TIG/MIG) with 4043/4047 filler is possible only in low-loading grades because molten Al reacts with B₄C to form brittle Al₃BC/AlB₂ and the weld pool is sluggish — mechanical fastening is common in racks.
What surface finishes work on B4C/6061-T651?
Sulfuric or hard anodize gives an uneven film because B₄C particles do not convert; chromate/trivalent conversion coating or paint is the usual protection, and mechanical polishing leaves particle relief.
Can B4C/6061-T651 be formed, bent or molded?
Supplied by powder metallurgy consolidation plus extrusion/rolling; cold forming limited to gentle bends (≥4t radius) in O or T4 temper, hot forming 400–480 °C for tighter radii.
What is the maximum service temperature of B4C/6061-T651?
B4C/6061-T651 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between B4C/6061-T651 and B4C/6061-O?
T651 is the default condition — standard stocked condition for flat neutron-absorber plate that will be machined to close tolerance without distortion. O: choose when the panel must be bent, roll-formed or deep-drawn before final ageing. Yield strength is 300 MPa in T651 versus 85 MPa in O.
Sources
- ASTM B932 — Standard Specification for Low-Carbon Nickel...(Aluminum-Alloy and Aluminum-Matrix Composite Neutron Absorbing Materials for Spent Nuclear Fuel Storage) — ASTM International (2014)
- ASTM B209 / Aluminum Association Teal Sheets (6061 matrix chemistry & temper definitions) — ASTM / The Aluminum Association (2021)
- ASM Handbook Vol. 21: Composites — Discontinuously Reinforced Aluminum — ASM International (2001)
- Al-B4C neutron absorber plate datasheets (Rio Tinto Alcan, Holtec Metamic, Ceradyne/3M, / ) — various producers (2023)
- NRC/EPRI neutron absorber material performance reports (Al-B4C MMC service data) — US NRC / EPRI (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.