Selection Guidelines and Decision Matrix

By Tong Wang

Explore lightweight material selection guidelines: Learn how to choose the most suitable materials for industries such as automotive, UAV, consumer electronics, and outdoor equipment based on different application scenarios (strength priority vs. cost priority).

Chapter 8: Selection Guidelines and Decision Matrix
8.1 Selection by Application: Strength Priority vs. Cost Priority
• Extreme Performance Scenarios (Strength Priority)
• Balanced Performance Scenarios (Cost-to-Performance Priority)
• Cost-Sensitive Scenarios (Cost Priority)
8.2 Material Combination Strategies: Structural Hierarchy and Hybrid Design
• Hierarchical Structural Design
• Hybrid Material Design
• Modular Design
8.3 Material Selection Recommendations by Industry
• Outdoor Equipment Industry
• Automotive Industry
• UAV Industry
• Consumer Electronics Industry
Table 8-1: Lightweight Material Selection Matrix by Industry
References

Chapter 8: Selection Guidelines and Decision Matrix

8.1 Selection by Application: Strength Priority vs. Cost Priority

In lightweight material selection, strength priority and cost priority are the two most fundamental decision dimensions. Depending on the requirements of different application scenarios, a systematic material selection framework can be established as follows:

• Extreme Performance Scenarios (Strength Priority):
  In fields highly sensitive to weight—such as aerospace, high-end racing, and high-performance unmanned aerial vehicles (UAVs)—magnesium-lithium (Mg–Li) alloys and continuous carbon fiber composites offer the best solutions.
  Mg–Li alloys, with a density of only 1.34–1.64 g/cm³, are currently the lightest metallic structural materials available. Continuous carbon fiber composites provide the highest specific strength and stiffness, making them ideal for primary load-bearing structures. In these fields, cost is a secondary factor, while performance metrics dominate material choice.

• Balanced Performance Scenarios (Cost-to-Performance Priority):
  In industries such as automotive, consumer electronics, and general industrial equipment, balance between performance and cost is crucial. Conventional magnesium alloys, aluminum alloys, and short carbon fiber composites provide effective compromises.
  For example, in automotive manufacturing, the use of magnesium alloys in vehicle components can improve fuel economy—every 100 kg reduction in vehicle weight can lower fuel consumption by 0.3–0.6 L per 100 km. In consumer electronics, aluminum alloys are a mainstream choice due to their favorable strength, light feel, and moderate cost.

• Cost-Sensitive Scenarios (Cost Priority):
  In construction, general-purpose industrial parts, and mass-consumption goods, cost often takes precedence. Glass fiber-reinforced composites and recycled aluminum alloys are the most common choices.
  Industry data shows that glass fiber composites dominate composite material usage in the automotive market, accounting for about 92%, while carbon fiber—though superior in performance—occupies only 0.6%. This clearly illustrates that in high-volume automotive production, cost remains the key driver for material selection.

8.2 Material Combination Strategies: Structural Hierarchy and Hybrid Design

In modern product design, a single material rarely meets all performance demands. Thus, material combination strategies have become increasingly essential. Through structured layering and hybrid use, designers can balance performance, weight, and cost optimally.

• Hierarchical Structural Design
  This approach tailors material selection to the function and loading conditions of each component.
  For example, in a new energy vehicle battery pack, the upper cover may use LFT-D polypropylene thermoplastic composites to meet requirements for lightweighting and insulation; the lower case may adopt aluminum alloy for strength and heat dissipation; and internal supports may use magnesium alloy or engineering plastics to further reduce weight.
  This structural hierarchy allows each part to perform at its material's peak potential.

• Hybrid Material Design
  This strategy integrates multiple materials within a single component. For example, in automotive body structures, a carbon fiber–aluminum alloy hybrid can be utilized—carbon fiber in high-stress zones and aluminum in general areas.
  Appropriate joining technologies such as ultrasonic or induction welding for thermoplastic composites ensure reliable material synergy.

• Modular Design
  Another effective combination method involves modularity. For instance, in automotive door modules, recycled carbon fiber thermoplastic materials can form the main body, with local metal inserts reinforcing critical joint areas.
  This not only enables lightweighting but also simplifies maintenance and recyclability.
  NIO’s “Car-to-Car” closed-loop recycling program exemplifies this practice—disassembling, melting, and recertifying aluminum alloy components from retired vehicles for use in new parts, building a sustainable mini-cycle of “retired vehicle → disassembly → smelting → new material → new component → vehicle.”

8.3 Material Selection Recommendations by Industry

(Domains: Outdoor, Automotive, UAV, Consumer Electronics)

Different industries, due to variations in operating environment, performance demand, and cost structure, emphasize distinct priorities in lightweight material selection:

• Outdoor Equipment Industry:
  Outdoor gear must be lightweight, durable, and environmentally resilient. Carbon fiber composites and aluminum alloys dominate this sector.
  Carbon fiber suits weight-critical items such as trekking poles or tent frames, while aluminum alloys are favored for cookware and water bottles.
  For professional-grade equipment, Mg–Li alloys can be used in key components to achieve ultimate weight reduction.

• Automotive Industry:
  Automotive lightweighting exhibits clear material diversification. Exterior panels can utilize thermoplastic composites, as demonstrated in the SAERTEX–Roctool composite hood; structural parts like A-pillars and bumper beams typically use high-strength aluminum or magnesium alloys; while battery packs combine LFT-D composites (upper cover) with aluminum alloys (lower case).
  Market estimates indicate that the global automotive composites market will reach $10.06 billion in 2025 and soar to $17.72 billion by 2030, representing a 12% compound annual growth rate (CAGR) between 2025 and 2030.

• Unmanned Aerial Vehicle (UAV) Industry:
  UAVs are extremely weight-sensitive, and lightweight materials directly determine flight endurance and payload capacity.
  High-end UAVs should prioritize carbon fiber composites for the main structure to maximize stiffness-to-weight ratio, while internal frames can use Mg–Li or aluminum alloys.
  Heat-dissipating parts such as motor mounts are best made from aluminum alloys for their excellent thermal conductivity.
  Notably, UAV propellers are now produced using thermoplastic continuous fiber technologies, such as those exhibited by HRC.

• Consumer Electronics Industry:
  Electronic products must balance light weight, aesthetics, and heat dissipation.
  Mg–Li alloys, with superb lightness and thermal conductivity, are now premier materials for high-end ultra-thin laptops. Smartphone frames and outer shells use aluminum alloys or ceramic composites, while internal thermal management components prefer high-conductivity aluminum or graphene composites.
  For parts requiring EMI shielding, Mg–Li alloys’ excellent electromagnetic protection enhances overall device reliability.

References

1.   Pencil News. 3D Printing: 15 Emerging Unicorns Leading Breakthroughs in Materials, Processes, and Applications.

2.   Shanghai Climate Week. Roundtable: Responsible Automotive Supply Chains and Sustainable Materials.

3.   3D Printing Tech Reference. 2024 Outlook: Breakthrough New Materials, Processes, and Applications in 3D Printing.