Raytron Technical Review RESEARCH ARTICLE
Mechanical Properties of Clad Structures
Received: 2025-12 Accepted: 2026-02 Published: 03/2026
DOI: 10.1234/raytron.2026.WP-01-05
1. Introduction
1.1 Clad structures Mechanicsadvantages
Clad structuresprovides Mechanical propertiescan material ：
vsCompare Performance
MEDIA TODO1.2 KeyMechanicsChallenges
2. Principles
2.1
for Clad structures（）：
VoigtModel（ ）：
Pparallel = Σi Vi Pi
(1) ：P = ，Vi = i volume fraction，Pi = i performance
VoigtReussanimation
0:30ReussModel（ ，）：
1/Pseries = Σi Vi/Pi
(2) 2.2 performance
2.3
Interface in ：
，showing
MEDIA TODO：
- ductility
- Interface
3.
3.1 stress-strain
Claddingmaterial stress-strainas ：
vs-
MEDIA TODOTypical：
- stage I： -
- stage II： -
- stage III： -
- stage IV： - LocalDeformation
- stage V：Fracture - Failure
3.2
for CCA（CuCladding，Al）：
animation，showing
0:25：
εyield,Al = σy,Al/EAl
(3)
εyield,Cu = σy,Cu/ECu
(4) 3.3 Tensile Strength
PredictionModel：
σUTS,clad = η · (Vc σUTS,c + Vm σUTS,m)
(5) ηefficiency （0.85-1.0）。
4.
4.1 Claddingmaterial
von Mises：
σ̄ = √[½((σ₁-σ₂)² + (σ₂-σ₃)² + (σ₃-σ₁)²)]
(6) for Claddingmaterial ，makes ：
σ̄clad = Σi Vi σ̄i
(7) 4.2 as
Model：
σ = K εⁿ
(8) for Claddingmaterial ：
σclad = Σi Vi Ki εni
(9) Diagram placeholder
MEDIA TODO4.3 Interfacefor Impact
：
Interfacein ：
τinterface = P/(πdLt)
(10) LtLength。
5.
5.1 Claddingmaterial Mechanism
multiple Mechanismsimultaneously role ：
Diagram placeholder
MEDIA TODO5.2 Drawing
Drawingprocess ：
σy = σy0 + K · εdrawn
(11) Diagram placeholder
MEDIA TODO5.3 Annealing
and ：
Diagram placeholder
MEDIA TODO6. Stress
6.1 Residual Stress
6.2 methods
Diagram placeholder
MEDIA TODO6.3 for Impact
6.4 ControlStrategy
7. Fatigue
7.1 Claddingmaterial FatigueMechanism
：
Diagram placeholder
MEDIA TODO7.2 S-NCurve
S-N
MEDIA TODO7.3 FatigueDesign
ImpactFatigue Life ：
- Surface：，Ra < 1.6 μm
- Interface：Delaminationdecreases ， > 40 MPa
- ：Tensiondecreases ，R > 0requires
- Environment：Corrosion，requires
7.4 Fatigue LifePrediction
Miner：
Σi (ni/Ni) = 1
(12) for Claddingmaterial ，makes methods：
Nclad = ηf · Nrule-of-mixtures
(13) ηf = 0.8-1.2，Interfacequality 。
8. DesignOptimization
8.1
8.2 OptimizationExample
：60% IACSconductivity，>300 MPaStrength，Low cost
8.3 applicationsDesign
9. Testing
9.1 TensionTesting
standardsMethods：
- ASTM E8：Cross-Section，σy, σUTS, %EL
- ASTM E111：，E
- ISO 6892：，
9.2 InterfaceStrengthTesting
9.3 FatigueTesting
Parameter：
- (R): 0.1, -1 -
- frequency: 10-50 Hz - Testingefficiency
- Environment: 、Control - Simulation
- : Conditions10-15 - Effective
10. Conclusion
10.1 Key
- Clad structuresthrough provides Mechanical properties
- provides performancePrediction
- Interfacequality for achieves Predictionperformanceimportant
- Residual StressControlensures DimensionsStability
- Fatigueas requires Interface
10.2 DesignRecommendations
- High strength：CCS - ensures conductivity
- conductivity：CCACu% - VerificationStrengthrequirements
- ：NCC - temperature
- FatigueKey：CCAANCC - Interfacequality
- sensitive：CCS or CCAstandards - cost
Figures
Clad Structure vs Homogeneous Material Performance Radar Chart
Constraint Effect Diagram, Showing Deformation Compatibility
Clad Material vs Component Material Stress-Strain Curve
Flow Stress Curve Comparison
Multiple Hardening Mechanisms Diagram
Drawing Hardening Curve
Annealing Temperature Impact on Properties Curve
Residual Stress Distribution Curve
Fatigue Crack Initiation and Propagation Path
S-N Curve Comparison
Tables
Table 1 Mechanical Property Tailoring
| Property | Homogeneous Material | Clad (Optimized) | Advantage |
|---|---|---|---|
| Strength | Material Fixed | Adjustable | Design Flexibility |
| Ductility | Trade-off with Strength | Simultaneously Optimizable | Better Balance |
| Weight | Density Fixed | Adjustable | Weight Reduction |
| Cost | Material Limited | Optimizable | Cost Saving |
Table 2 Mechanical Challenges of Clad Structures
| Challenge | Source | Impact |
|---|---|---|
| Stress Concentration | Interface | Premature Failure |
| PoorDifferenceYield | DifferentYield Strength | Complex Behavior |
| Residual Stress | Processing | DimensionStability |
| Interface Failure | BondingWeak | Delamination |
Table 3 MixedApplications
| Property | Model | Formula | Applicability |
|---|---|---|---|
| Elasticity | Voigt | E = V₁E₁ + V₂E₂ | Axial |
| Yield Strength | σ_y = f(V, σ₁, σ₂) | Complex | |
| UTS | Voigt | σ_UTS ≈ V₁σ₁ + V₂σ₂ | Approximate |
| Density | Voigt | ρ = V₁ρ₁ + V₂ρ₂ | Precise |
Table 4 Common CladdingMaterial YieldOrder
| Material | Core Materialσ_y (MPa) | Cladding Layerσ_y (MPa) | PreYield |
|---|---|---|---|
| CCA | 40 (Al) | 70 (Cu) | Core Material (Al) |
| CCS | 350 (Steel) | 70 (Cu) | Cladding Layer (Cu) |
| NCC | 70 (Cu) | 150 (Ni) | Core Material (Cu) |
Table 5 UTSPrediction Accuracy
| Material | Prediction (MPa) | Measured (MPa) | Error (%) |
|---|---|---|---|
| CCA-15% | 170 | 165 | +3% |
| CCS-20% | 420 | 435 | -3% |
| NCC-10% | 280 | 275 | +2% |
Table 6 Processing HardeningParameter
| Material | K (MPa) | n | K_clad (MPa) | n_clad |
|---|---|---|---|---|
| PureAl | 150 | 0.25 | - | - |
| PureCu | 320 | 0.30 | - | - |
| CCA-15% | - | - | 240 | 0.28 |
Table 7 InterfaceShear Stress Requirements
| Material | Applied Stress (MPa) | τ_required (MPa) | Bonding Strength (MPa) | SafetyCoefficient |
|---|---|---|---|---|
| CCA | 150 | 12 | 45 | 3.8 |
| CCS | 400 | 35 | 55 | 1.6 |
| NCC | 250 | 20 | 50 | 2.5 |
Table 8 Drawing HardeningCoefficient
| Material | K_hard (MPa) | n_hard | MaximumReducedDiameter (%) |
|---|---|---|---|
| CCA | 180 | 0.45 | 90 |
| CCS | 350 | 0.35 | 85 |
| NCC | 220 | 0.40 | 92 |
Table 9 AnnealingParameter
| Material | Recovery Temperature | Re-Crystallization Temperature | Grain Dimension (μm) |
|---|---|---|---|
| CCA | 150-250°C | 250-350°C | 20-50 |
| CCS | 300-400°C | 500-600°C | 10-30 |
| NCC | 200-300°C | 400-500°C | 15-40 |
Table 10 Residual StressMeasuredTechnology
| Method | Principle | Resolution | DeepDegreeScope |
|---|---|---|---|
| X-RayDiffraction | Lattice Strain | 10 MPa | 10-20 μm |
| NeutronDiffraction | Lattice Strain | 20 MPa | mmScope |
| StressRelaxation | 10 MPa | 0.5-2 mm | |
| Curvature | Stoney | Surface | - |
Table 11 Residual StressImpact
| Effect | Front | Surface |
|---|---|---|
| Yield Behavior | Pre- StressImprovableHighApparentσ_y | PrematureYield |
| Fatigue | SurfaceCompressive Stress | Accelerated CrackGeneration |
| DimensionStability | - | |
| Stress Corrosion | - | AcceleratedErosion |
Table 12 Fatigue Properties
| Material | FatigueLimit (MPa) | DurabilityRatio | 10⁶Cycle Service Life |
|---|---|---|---|
| PureCu | 70 | 0.35 | 100 MPa |
| CCA-15% | 55 | 0.33 | 80 MPa |
| CCS-20% | 150 | 0.35 | 200 MPa |
| NCC-10% | 90 | 0.35 | 130 MPa |
Table 13 DesignTrade-offMatrix
| High strength | HighConductivity | LowWeight | Low cost |
|---|---|---|---|
| ↑ Steel Core | ↑ Cu Cladding | ↑ AlCore | ↓ CuContent |
| ↑ Processing Hardening | ↓ IMC | ↓ Density | Process Efficiency |
| ↑ Cu% | ↓ Impurity | ↓ Cu% | standardsetc. Grade |
Table 14 Optimization ResultsExample
| Option | Configuration | σ_UTS (MPa) | Conductivity | Cost Index |
|---|---|---|---|---|
| A | CCS-25% Cu | 380 | 35% IACS | 0.35 |
| B | CCA-80% Cu | 180 | 80% IACS | 0.85 |
| C | CCAA-6101, 20% Cu | 280 | 62% IACS | 0.50 |
| MostExcellent | CCAA-6101, 18% Cu | 310 | 60% IACS | 0.48 |
Table 15 ApplicationsDesign Guide
| Application | ExcellentPre Grade | Recommendation |
|---|---|---|
| Building Wire | Cost | CCAstandards |
| Automotive | Weight+ Fatigue | CCAA Optimization |
| Aerospace | Temperature+Weight | NCC |
| Grounding | Strength+Anti-theft | CCS |
| RF Cable | SurfaceConductivity | CCA or SCC |
References
- Mechanical Behavior of Materials (2nd ed.) McGraw-Hill (2000)
- Mechanical Metallurgy (3rd ed.) McGraw-Hill (1986)
- Engineering Materials 1 (3rd ed.) Butterworth-Heinemann (2005)
- Mechanical Behavior of Materials McGraw-Hill (1990)
- Mechanics of Solid Materials Cambridge University Press (1990)
- Mechanical Behavior of Materials (4th ed.) Pearson (2012)
- Fatigue of Materials (2nd ed.) Cambridge University Press (1998)
- Metal Fatigue in Engineering (2nd ed.) Wiley (2001)
- ASTM E8/E8M: Standard Test Methods for Tension Testing of Metallic Materials ASTM (2022)
- Mechanical Properties of Bimetallic Conductors Internal Report TR-2025-078 (2025)