Give the distinctive features, limitations, and applications of the following alloy groups: titanium alloys, refractory metals, superalloys and noble metals.

Answer: Titanium alloys have a high strength-to-weight ratio, excellent corrosion resistance, and good biocompatibility. However, they have high production costs, poor wear resistance, and limited high-temperature applications. They are commonly used in the aerospace industry, medical implants, and high-performance sports cars. Refractory metals are known for their high melting points, good wear resistance, and strong resistance to deformation at high temperatures. Their limitations include high density, limited ductility and toughness at low temperatures, and expensive and challenging fabrication. Their applications can be found in the lighting industry, high-temperature furnaces, and rocket engines. Superalloys exhibit high-temperature strength, resistance to creep, and good corrosion and oxidation resistance. They have expensive production, are difficult to fabricate, machine, and weld, and some are prone to stress-corrosion cracking. They are widely used in the aerospace industry, power generation industry, and chemical and petrochemical industries. Noble metals have high resistance to corrosion and oxidation, excellent electrical and thermal conductivity, and a lustrous appearance. Their limitations include being expensive and rare, limited availability, and not being suitable for high-strength applications. Noble metals are used in jewelry, electronics, and catalytic converters.