Abstract: An aluminum alloy for use in castings, comprising 0.0005-0.01 weight % of Fe, 0.0005-0.01 weight % of Si, 2.5-6.5 weight % of Cu, 0.10-0.50 weight % of Mg, 0.001-0.40 weight % of Mn, 0.10-0.50 weight % of Ti, 0.20-1.2 weight % of Ag, 0.002-0.01 weight % of B, no more than 0.01 weight % of any other individual component aside from Al, and the balance Al. The aluminum alloy is thereby designed to provide improved toughness without detracting from tensile strength, proof stress, and hardness.

Abstract: The present invention relates to a vibration-damping metal sheet.Conventional vibration-damping metal sheets such as single metal sheets of Mn-Cu base alloys, etc., and sandwich steel sheets having an intermediate plastic material had individually some disadvantages in connection with critical temperatures for use, heat resistance, weldability, conductivity and other properties.In the present invention, metal plates (1) and (2) are joined together through minute inclusions (3) permitted to be substantially uniformly present therebetween and bit thereinto and, optionally, through the diffusion of a portion of the metal plates into which the minute inclusions are bit. At another portion, the metal plates (1) and (2) only come into contact with each other. Metal or ceramic powders, or wiry or network materials may be used as the minute inclusions (3).