The strength comparison between nickel and aluminum depends on the specific type of strength being measured (e.g., tensile strength, yield strength, hardness) and the form of the metals (pure vs. alloys). Here's a detailed breakdown:
Pure nickel: It has a tensile strength of about 345 MPa (megapascals) and a yield strength of around 140 MPa. It is relatively ductile and resistant to corrosion, but its strength is moderate compared to many alloys.
Pure aluminum: Pure aluminum is much weaker, with a tensile strength of only ~90 MPa and a yield strength of ~30 MPa. It is soft and highly malleable, making it unsuitable for high-strength applications in its pure form.
In their pure states, nickel is significantly stronger than aluminum in both tensile and yield strength.
Most industrial applications use alloys (metals mixed with other elements) to enhance strength, and here the comparison becomes more nuanced:
Nickel alloys: Alloys like Inconel (nickel-chromium-based) or Monel (nickel-copper) have exceptional strength, especially at high temperatures. For example:
Inconel 718 has a tensile strength of ~1,400 MPa and a yield strength of ~1,200 MPa.
These alloys retain strength even at temperatures above 600°C, making them ideal for aerospace or high-heat applications.
Aluminum alloys: Alloys like 6061-T6 or 7075-T6 are far stronger than pure aluminum:
6061-T6 has a tensile strength of ~310 MPa and a yield strength of ~276 MPa.
7075-T6 (a high-strength alloy) reaches a tensile strength of ~572 MPa and a yield strength of ~503 MPa.
However, aluminum alloys lose strength rapidly at temperatures above 150–200°C, limiting their use in high-heat environments.
Hardness (a measure of resistance to deformation) also favors nickel in most cases:
Pure nickel has a Brinell hardness of ~80 HB.
Pure aluminum has a Brinell hardness of only ~25 HB.
High-strength aluminum alloys (e.g., 7075-T6) can reach ~150 HB, but nickel alloys like Inconel often exceed 200 HB, making them harder and more wear-resistant.
Aluminum has a lower density (~2.7 g/cm³) compared to nickel (~8.9 g/cm³). This means aluminum alloys often have a better strength-to-weight ratio, which is critical in applications like aerospace or automotive design where weight reduction is key. For example, 7075-T6 aluminum has a strength-to-weight ratio (~210 kN·m/kg) that surpasses many nickel alloys, even though nickel alloys have higher absolute strength.
In terms of absolute strength (tensile, yield, hardness), nickel and its alloys are generally stronger than aluminum and its alloys, especially at high temperatures. However, aluminum alloys excel in strength-to-weight ratio, making them preferable in weight-sensitive applications. The "strength" of each depends on the specific requirement (e.g., high heat resistance vs. lightweight design).
