For design engineers who need tensile strength approaching mild steel but at one-third the weight, 2014 aluminum (AlCu4SiMg) often fits the bill — provided the part won’t see sustained exposure to moisture or corrosive environments. In the T6 or T651 temper, 2014 delivers ultimate tensile strength around 483 MPa (70 ksi), placing it among the strongest commercially available aluminum alloys. However, its copper content also makes it one of the least corrosion-resistant aluminum grades, and this trade-off must be weighed early in material selection.
Alloy Identity and Standards Cross-Reference
2014 belongs to the 2xxx wrought aluminum series, defined by copper as the primary alloying element. The nominal composition Al-4.4Cu-0.8Si-0.8Mn-0.5Mg places it squarely in the heat-treatable, precipitation-hardening category. Key standards and specifications include:
- ASTM B209 — Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- AMS 4028 — Aluminum Alloy Sheet and Plate, 4.4Cu-1.5Mg-0.6Mn (2014-T6), Solution Heat Treated
- AMS 4121 — Aluminum Alloy Bars and Rods, 2014-T6
- AMS 4134 — Aluminum Alloy Forgings, 2014-T6
- QQ-A-250/3 — Federal Specification for 2014 Plate and Sheet (legacy, still referenced)
- EN AW-2014 / EN 573-3 — European designation; close chemical match
- ISO 6361-2 — Wrought aluminium alloy sheet and plate
Important: EN AW-2014A is often listed as the “European equivalent,” but its permitted composition ranges differ from the ASTM B209 specification for 2014. The two are approximate substitutes, not direct drop-in replacements. Always confirm the governing specification on the drawing before substitution.
Tempers and Supply Conditions
| Temper | Condition | Typical Application Context |
|---|---|---|
| 2014-O | Annealed — lowest strength, maximum formability | Forming blanks prior to solution heat treatment; rarely used as final temper |
| 2014-T4 | Solution heat treated and naturally aged to stable condition | Parts that will be formed after solution treatment; moderate strength with better ductility than T6 |
| 2014-T6 | Solution heat treated and artificially aged | Maximum strength temper; typical for machined components, fittings, and structural parts |
| 2014-T651 | T6 with stress relief by stretching (1.5-3% permanent set) | Plate and bar stock for machining; minimizes distortion during material removal |
| 2014-T62 | Solution heat treated by user from O or F temper, then artificially aged | When T6 is specified but stock in T4 was formed before final aging |
For CNC machining, T651 is the preferred starting condition. The stress-relief stretch reduces residual stresses that would otherwise cause the part to warp as asymmetric material is removed. Skipping T651 and machining from unstretched T6 plate routinely leads to out-of-tolerance flatness on thin-walled or asymmetric parts.
Chemical Composition (ASTM B209)
| Element | Weight % (min) | Weight % (max) |
|---|---|---|
| Copper (Cu) | 3.9 | 5.0 |
| Silicon (Si) | 0.5 | 1.2 |
| Manganese (Mn) | 0.4 | 1.2 |
| Magnesium (Mg) | 0.2 | 0.8 |
| Iron (Fe) | — | 0.7 |
| Chromium (Cr) | — | 0.10 |
| Zinc (Zn) | — | 0.25 |
| Titanium (Ti) | — | 0.15 |
| Others (each) | — | 0.05 |
| Others (total) | — | 0.15 |
| Aluminum (Al) | Remainder | |
The high copper content (3.9-5.0%) is the key to 2014’s strength — CuAl₂ precipitates provide the hardening response during artificial aging. The silicon and magnesium contribute to Mg₂Si precipitation, adding further strengthening. But this copper content also makes the alloy susceptible to intergranular corrosion and stress-corrosion cracking, particularly in the T6 temper when stressed in the short-transverse direction.
Typical Mechanical Properties
Values per ASTM B209 for 2014-T6 and T651 plate. These are minimum specification values; actual mill product typically exceeds them.
| Property | 2014-T6 / T651 (Plate ≤ 25 mm) | 2014-T6 / T651 (Plate 25-50 mm) | Test Method |
|---|---|---|---|
| Tensile Strength, Ultimate | ≥ 483 MPa (70 ksi) | ≥ 483 MPa (70 ksi) | ASTM E8 / ISO 6892-1 |
| Tensile Strength, Yield (0.2% offset) | ≥ 414 MPa (60 ksi) | ≥ 414 MPa (60 ksi) | ASTM E8 / ISO 6892-1 |
| Elongation in 50 mm (2 in) | ≥ 7% | ≥ 6% (thickness effect) | ASTM E8 |
| Brinell Hardness | ~135 HB (500 kgf, 10 mm ball) | ~130 HB | ASTM E10 |
| Modulus of Elasticity | ~73 GPa (10.6 × 10⁶ psi) — typical | ASTM E111 | |
| Shear Strength | ~290 MPa (42 ksi) — typical | ASTM B769 | |
| Fatigue Strength (5 × 10⁸ cycles, R=−1, smooth) | ~125 MPa (18 ksi) — typical | Rotating beam | |
Note on thickness: 2014-T651 plate over 50 mm may show lower tensile properties at the center due to quench rate limitations. When thick sections are ordered, mill certificates should confirm through-thickness properties if critical.
Corrosion Behavior and Limitations
This is where 2014 diverges sharply from 6061 or 7075. 2014 has poor general corrosion resistance compared to most other aluminum alloys — it ranks near the bottom of the 2xxx-8xxx series. Key behaviors:
- Intergranular corrosion: Copper-rich grain boundaries create galvanic micro-cells. In the T6 temper, susceptibility is highest. T4 temper (naturally aged) shows better resistance because the precipitate distribution is less continuous.
- Stress-corrosion cracking (SCC): 2014-T6 is susceptible in the short-transverse (through-thickness) direction, especially in thick sections. AMS 4028 plate is typically procured with SCC testing requirement per ASTM G47 when specified for structural aerospace use.
- Galvanic corrosion: When coupled with dissimilar metals (steel fasteners, copper alloys), 2014 will be the anode and corrode preferentially. Isolation with wet-install sealants or non-conductive coatings is standard practice.
- Not for marine or chemical exposure: If your part will see salt spray, acidic condensate, or industrial atmosphere without protective coating, 2014 is likely the wrong choice. Consider 6061-T6 (moderate corrosion resistance) or 5052-H32 (excellent) instead.
Where 2014 is used in corrosive environments, it is almost always clad with a thin layer of high-purity aluminum (Alclad 2014) or protected with chromate conversion coating (MIL-DTL-5541 Type I or II) plus primer and topcoat. Unclad 2014-T6 should not be used bare in structural applications exposed to weather.
CNC Machining Characteristics
2014 machines differently from the more common 6061. Here is what you will notice on the shop floor:
Machinability Rating
Roughly 70-80% of 6061-T6 in terms of tool life and surface finish at equivalent parameters. The copper-rich intermetallic particles are abrasive, causing faster flank wear on carbide tools compared to 6061. On the positive side, 2014 produces short, brittle chips at typical feeds — chip control is generally better than 6061, which can be stringy at lower feeds.
Starting Parameters (T651 Plate, Rigid VMC, Solid Carbide)
All values below are starting references only. Actual parameters depend on machine rigidity, tool holder, coolant delivery, workpiece fixturing, and specific tool geometry. Confirm with a test cut and adjust.
| Operation | Cutting Speed | Feed per Tooth | Radial/Axial DOC | Tool Note |
|---|---|---|---|---|
| Rough Milling (2-3 flute) | 200-400 m/min (650-1300 SFM) | 0.10-0.25 mm/tooth | aₑ 30-70% D, aₚ up to 1.5×D | Uncoated polished carbide or ZrN; high helix preferred |
| Finish Milling (3-4 flute) | 250-500 m/min (800-1600 SFM) | 0.05-0.12 mm/tooth | aₑ 0.3-1.0 mm, aₚ per feature | DLC or polished uncoated carbide for best finish |
| Drilling (carbide, 6-12 mm Ø) | 80-180 m/min (260-590 SFM) | 0.10-0.25 mm/rev | — | Polished flutes, 130-140° point angle |
| Tapping (6-12 mm) | 10-20 m/min (33-65 SFM) | Pitch-dependent | — | Spiral-flute tap; emulsion coolant essential |
| Turning (carbide insert) | 200-500 m/min (650-1600 SFM) | 0.10-0.30 mm/rev (rough), 0.05-0.15 mm/rev (finish) | 1-4 mm rough, 0.2-0.5 mm finish | Positive rake, polished top surface; K10/K20 grade |
Tooling and Coolant
- Carbide grades: K10-K20 (C2-C3) uncoated or with DLC/ZrN coatings perform well. TiAlN and AlTiN coatings designed for steel add friction on aluminum and encourage built-up edge (BUE). Avoid them on 2014.
- Coolant: Flood coolant (5-8% soluble oil emulsion) is strongly recommended. Minimum quantity lubrication (MQL) can work for finishing but risks BUE in roughing. 2014’s copper content makes it slightly more prone to BUE than 6061, so don’t skimp on coolant flow.
- Built-up edge management: If you see material adhering to the cutting edge, check coolant concentration first. If that doesn’t help, increase cutting speed to raise the tool-chip interface temperature above the BUE formation range, or switch to a polished (harder, smoother) carbide grade.
Dimensional Stability
Parts machined from 2014-T651 plate typically exhibit better dimensional stability than those from unstretched T6. However, for parts requiring tight tolerances across large areas, a stress-relief cycle (200-230°C for 2-4 hours, then furnace or air cool) before final machining can further reduce movement. This temperature range is below the aging temperature and does not degrade T6 mechanical properties.
Surface Treatments
- Anodizing: 2014 anodizes, but the resulting coating is yellowish to brownish-gray and lacks the transparency and corrosion protection of coatings on 6xxx alloys. Sulfuric acid anodizing (Type II, MIL-A-8625) provides approximately 5-25 μm coating thickness. Hard anodizing (Type III) can achieve 25-75 μm but the dark, non-decorative appearance limits its use to functional applications. Decorative clear anodizing is not recommended for 2014 — the copper-rich intermetallics cause a mottled, dark appearance.
- Chemical conversion coating: Chromate conversion per MIL-DTL-5541 (Alodine/Chem-film) provides good paint adhesion and moderate corrosion protection, adding negligible thickness. This is the most common pre-paint treatment for 2014 aerospace parts.
- Cladding: Alclad 2014 (2014 core with 1xxx-series pure aluminum cladding on both surfaces) provides the corrosion resistance of pure aluminum with the strength of 2014. The cladding layer thickness is specified as a percentage of total thickness (typically 2.5-5% per side). Machining removes cladding, so Alclad is more relevant for sheet metal and lightly machined plate parts.
Comparison with 2024 and 7075
| Property | 2014-T6 | 2024-T3 | 7075-T6 |
|---|---|---|---|
| UTS (typical, plate) | ~483 MPa | ~470 MPa | ~572 MPa |
| YS (typical, plate) | ~414 MPa | ~325 MPa | ~503 MPa |
| Elongation (typical) | ~7-10% | ~15-20% | ~8-11% |
| Machinability vs 6061 | 70-80% | 65-75% | 60-70% |
| Corrosion resistance | Poor | Poor | Fair-Poor |
| Fatigue strength (typical) | ~125 MPa | ~140 MPa | ~160 MPa |
| SCC resistance (ST direction) | Low (T6) | Low (T3/T4) | Low (T6) |
| Weldability (fusion) | Not recommended | Not recommended | Not recommended |
When to choose 2014 over 2024: 2014-T6 has higher yield strength (414 vs 325 MPa) and is typically available as T651 stress-relieved plate. If your part requires maximum compressive yield strength and must maintain flatness after machining, 2014-T651 often beats 2024-T351. However, 2024-T3/T4 offers far better fracture toughness and fatigue crack growth resistance — critical for tension-dominated structural applications.
When to choose 2014 over 7075: 2014 is approximately 15-20% lower cost than 7075 in plate form and machines with slightly longer tool life. If the design has margin on ultimate strength and the primary driver is compressive yield strength, 2014-T651 can be a cost-effective alternative.
Typical Applications
- Aircraft structural forgings: Wing spars, fuselage frames, bulkhead fittings where high compressive yield matters and Alclad or coating provides corrosion protection.
- Heavy-duty automotive: Connecting rods (forged and fully machined), pistons (forged), suspension rockers in motorsport where service intervals allow inspection.
- Ordnance components: Historically used for military hardware requiring high strength-to-weight ratio with managed service life.
- High-pressure hydraulic manifolds: When 6061-T6 lacks the compressive strength for high-cycle pressure fatigue but 7075 cost or SCC concerns rule it out.
- Precision jigs and fixtures: T651 plate machined into assembly fixtures where flatness stability and moderate weight are needed.
RFQ Information Checklist
When requesting a quote for 2014 CNC machined parts, include the following to get an accurate price and lead time:
- Full material specification: AA 2014-T651 or AMS 4028, not just “2014” or “aluminum.” The temper and governing standard directly affect material cost and availability.
- Drawing or 3D model: PDF with GD&T or STEP file. Call out critical datum features.
- Quantity and delivery schedule: Prototype run vs. production volumes. 2014-T651 plate may have minimum-order surcharges at small quantities.
- Surface treatment requirements: Anodize type and color, chem-film, paint system, or none. If anodizing, specify whether masking of threaded or press-fit features is required.
- Inspection requirements: Dimensional report (FAI per AS9102 for aerospace), material certifications (mill test report to ASTM B209 or AMS), NDT (penetrant inspection for surface-breaking defects if the part is fracture-critical).
- Corrosion protection: If Alclad is required, specify clad thickness and whether it must remain intact on machined surfaces (limits machining depth from clad side).
Send your drawings, material specifications, temper, quantity, and surface finish requirements to our engineering team for a detailed quotation.
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