Copper in architecture used in residential and commercial building structures. Variations in color stem primarily from differences in the alloy chemical composition. Some of the more popular copper alloys and their associated Unified Numbering System (UNS) numbers developed by ASTM and SAE are as follows: In practice, the term ‘bronze’ may be used for a variety of copper alloys with little or no tin if they resemble true bronzes in color. Further information on architectural copper alloys is available. The criteria by which copper and copper alloys are selected for architectural projects include color, strength, hardness, resistance to fatigue and corrosion, electrical and
Shape-memory alloy Shape-memory alloy A shape-memory alloy (SMA, smart metal, memory metal, memory alloy, muscle wire, smart alloy) is an alloy that "remembers" its original shape and that when deformed returns to its pre-deformed shape when heated. This material is a lightweight, solid-state alternative to conventional actuators such as hydraulic, pneumatic, and motor-based systems. Shape-memory alloys have applications in robotics and automotive, aerospace and biomedical industries. The two most prevalent shape-memory alloys are copper-aluminium-nickel, and nickel-titanium (NiTi) alloys but SMAs can also be created by alloying zinc, copper, gold and iron. Although iron-based and copper-based SMAs, such as Fe-Mn-Si, Cu-Zn-Al and Cu-Al-Ni,