The addition of different metal elements in an alloy can significantly affect its mechanical properties (such as strength, hardness, ductility, toughness, corrosion resistance, etc.). The following are the roles of common metal elements in alloys and their effects on mechanical properties:

1. Carbon (C)

Use: Mainly found in steel and cast iron, forming carbides with iron (such as Fe3C).

Influence:

Strength/Hardness: Increased carbon content significantly increases hardness and strength (such as high carbon steel), but excessive amounts can lead to brittleness.

Ductility: The higher the carbon content, the lower the ductility and toughness.

Weldability: High carbon steel has poor welding properties.

2. Chromium (Cr)

Use: Key element for stainless steel (such as 304, 316) and tool steel.

Influence:

Corrosion resistance: Forms a passive oxide film (Cr2O3) to improve oxidation resistance and corrosion resistance.

Hardness/Strength: Forms carbides with carbon (such as Cr23C6) to improve hardness and wear resistance.

High temperature performance: Enhances high temperature strength (such as heat-resistant steel).

3. Nickel (Ni)

Applications: stainless steel (such as 304), high temperature alloys (such as Inconel) and corrosion resistant alloys.

Influence:

Toughness: Improves low temperature toughness and ductility (such as nickel steel for low temperature environments).

Corrosion resistance: Enhances resistance to acids and alkalis.

Austenite stabilization: In stainless steel, it cooperates with chromium to form an austenitic structure (such as 304 steel).

4. Molybdenum (Mo)

Applications: high strength steel (such as 4140), stainless steel (such as 316) and high temperature alloys.

Influence:

Strength/heat resistance: Improves high temperature strength and creep resistance.

Corrosion resistance: Enhances resistance to chloride stress corrosion (such as 316 stainless steel).

Grain refinement: Improves hardenability.

5. Manganese (Mn)

Applications: carbon steel (such as A36), high strength low alloy steel (HSLA) and austenitic manganese steel (such as Hadfield steel).

Influence:

Deoxidation/desulfurization: Reduces the harmful effects of sulfur (forms MnS instead of FeS).

Hardenability: Improves hardenability and wear resistance (e.g. high manganese steel for excavator buckets).

Austenite stabilization: Partial nickel replacement in stainless steel.

6. Silicon (Si)

Uses: Spring steel (e.g. 65Mn), electrical steel, and aluminum alloys (e.g. 4xxx series).

Influencet:

Strength/elasticity: Improves the strength and elastic limit of steel (e.g. silicon-manganese spring steel).

Deoxidizer: Removes oxygen during steelmaking.

Magnetic properties: Improves the magnetic permeability of electrical steel.

7. Aluminum (Al)

Uses: Aluminum alloys (e.g. 6061), high-temperature alloys (e.g. Fe-Cr-Al), and deoxidizers.

Influence:

Lightweighting: Reduces density (aluminum alloys are about 2/3 lighter than steel).

Corrosion resistance: Forms Al2O3 protective film.

Grain refinement: Inhibits grain growth in steel.

8. Titanium (Ti)

Applications: Titanium alloys (e.g. Ti-6Al-4V), stainless steels (e.g. 321), and high-temperature alloys.

Influence:

Strength/weight ratio: Titanium alloys have extremely high specific strength.

Corrosion resistance: Resists seawater and chloride corrosion.

Carbide formation: Fixes carbon in steel to prevent intergranular corrosion (e.g. 321 stainless steel).

9. Copper (Cu)

Applications: Brass (Cu-Zn), bronze (Cu-Sn), and precipitation-hardening steels (e.g. 17-4PH).

Influence:

Corrosion resistance: Improves atmospheric corrosion resistance (e.g. weathering steel).

Electrical/thermal conductivity: Copper alloys have excellent electrical conductivity.

Precipitation strengthening: Forms ε-Cu phase in steel (e.g. 17-4PH stainless steel).

10. Vanadium (V)

Applications: Tool steels (e.g. D2), high-strength low-alloy steels (HSLA).

Influence:

Grain refinement: Formation of carbonitrides (such as VC) to inhibit grain growth.

Strength/toughness: Improve strength while maintaining toughness (such as HSLA steel).

11. Tungsten (W)

Applications: High-speed steel (such as M2), cemented carbide (WC-Co) and high-temperature alloys.

Influence:

High-temperature hardness: Formation of wear-resistant carbides (such as W2C).

Red hardness: High-speed steel maintains hardness at high temperatures.

12. Zinc (Zn)

Applications: Galvanized steel (rust prevention), brass (Cu-Zn) and aluminum alloys (such as 7xxx series).

Influence:

Sacrificial anode protection: The zinc layer protects the steel matrix.

Strength: Forms a strengthening phase in aluminum alloys (such as Zn-Mg-Cu, 7075 aluminum alloy).

Summary: The core influence of elements on mechanical properties.

By adjusting the content and combination of these elements, alloys can be designed to meet specific needs (such as high-strength steels, corrosion-resistant alloys, or high-temperature alloys).