When comparing bronze, steel, and aluminum sculptures, thermal expansion is a critical factor influencing their durability and structural integrity. Bronze, an alloy primarily of copper and tin, has a moderate thermal expansion coefficient (around 18 × 10⁻⁶/°C), making it less prone to warping under temperature fluctuations compared to aluminum (23 × 10⁻⁶/°C), which expands more significantly. Steel, with a lower expansion rate (approximately 12 × 10⁻⁶/°C), offers greater stability in extreme environments.

Bronze sculptures are favored for outdoor installations due to their balanced expansion properties, resisting cracks over time. Aluminum, while lightweight, may require design adjustments to accommodate its higher expansion. Steel’s minimal expansion makes it ideal for large-scale or precision works. Understanding these differences helps artists and collectors choose the right material for longevity and aesthetic preservation.