Core Viewpoint - The article provides a comprehensive guide on material selection based on various mechanical properties such as Young's modulus, strength, and cost, emphasizing the importance of choosing the right materials for specific applications. Group 1: Young's Modulus and Density - When hard materials are needed, such as for top beams or bicycle frames, materials at the top of the chart should be selected [2] - For low-density materials, such as packaging foam, materials on the left side of the chart are recommended [2] - Finding materials that are both rigid and lightweight is challenging, and composite materials are often a good choice [3] Group 2: Young's Modulus and Cost - For hard materials, the top materials in the chart should be chosen for applications like top beams and bicycle frames [14] - For low-cost materials, those on the left side of the chart are preferred [14] - If a cheap and hard material is required, materials in the upper left corner of the chart, mostly metals and ceramics, should be selected [15] Group 3: Strength and Density - The strength indicated in the chart refers to tensile strength, with ceramics showing compressive strength [26] - High-strength and low-density materials are located in the upper left part of the graph [26] - Strength is a critical indicator of a part's ability to resist failure under load [26] Group 4: Strength and Cost - The strength indicated is tensile strength, except for ceramics which indicate compressive strength [38] - Many applications require materials with high strength, such as screwdrivers and seat belts, but these materials are often expensive [38] - Only a few materials can meet both strength and cost requirements, typically found in the upper left part of the chart [38] Group 5: Strength and Toughness - The strength indicated is tensile strength, while ceramics indicate compressive strength [50] - Typically, materials with poor toughness also have low strength; increasing strength may reduce toughness [50] - Strength measures a material's ability to resist external forces, while toughness measures its ability to absorb energy before failure [50] Group 6: Strength and Elongation at Break - Ceramics have very low elongation at break (<1%); metals have moderate elongation (1-50%); thermoplastics have high elongation (>100%) [61] - Rubber exhibits long-term elastic elongation, while thermosetting polymers have low elongation (<5%) [61] Group 7: Strength and Maximum Working Temperature - The chart applies to components used in environments where working temperatures exceed room temperature, such as cookware and automotive parts [73] - Polymers have lower maximum working temperatures, metals have medium, and ceramics can withstand very high temperatures [73] Group 8: Specific Strength and Specific Stiffness - Specific strength is defined as strength divided by material density, while specific stiffness is stiffness divided by material density [84] - High strength and high stiffness usually coexist, as they largely depend on the bonding forces between atoms [84] Group 9: Resistivity and Cost - The chart is primarily for selecting materials that require low prices and good electrical insulation or conductivity [97] - Good electrical conductors are typically good thermal conductors, while good electrical insulators are good thermal insulators [97] Group 10: Recyclability and Cost - The chart identifies materials' recyclability features, especially for expensive and recyclable materials [108] - Metals are particularly suitable for recycling due to ease of sorting and remelting, while ceramics are rarely recycled [108] Group 11: Production Energy Consumption and Cost - The energy consumed in producing a material is a factor in raw material costs, with most materials located in the low-cost/low-energy or high-cost/high-energy quadrants [121] - Metals often require significant energy for extraction, such as aluminum production consuming a substantial portion of total energy in the U.S. [123]