Guitar strings made of a magnetic copper-nickel-tin-manganese alloy are disclosed. Also disclosed are processing steps that can be performed to fabricate the guitar strings from the alloy. Further described herein are alternative uses for the strings on other electric stringed instruments.

A beryllium-free high-strength copper alloy includes, about 10-30 vol % of L1.sub.2-(Ni,Cu).sub.3(Al,Sn), and substantially excludes cellular discontinuous precipitation around grain boundaries. The alloy may include at least one component selected from the group consisting of: Ag, Cr, Mn, Nb, Ti, and V, and the balance Cu.

A beryllium-free high-strength copper alloy includes, about 10-30 vol % of L1.sub.2-(Ni,Cu).sub.3(Al,Sn), and substantially excludes cellular discontinuous precipitation around grain boundaries. The alloy may include at least one component selected from the group consisting of: Ag, Cr, Mn, Nb, Ti, and V, and the balance Cu.

A copper alloy containing Ni: 1.5%-3.6% and Si: 0.3%-1.0% in terms of mass percent with the remainder consisting of copper and unavoidable impurities, wherein: the average crystal grain size of the crystal grains in the copper alloy is 5 to 30 μm; the area ratio of the crystal grains having crystal grain sizes not less than twice the average crystal grain size is not less than 3%; and the ratio of the area of cube orientation grains to the area of the crystal grains having crystal grain sizes not less than twice the average crystal grain size is not less than 50%.

A copper alloy containing Ni: 1.5%-3.6% and Si: 0.3%-1.0% in terms of mass percent with the remainder consisting of copper and unavoidable impurities, wherein: the average crystal grain size of the crystal grains in the copper alloy is 5 to 30 μm; the area ratio of the crystal grains having crystal grain sizes not less than twice the average crystal grain size is not less than 3%; and the ratio of the area of cube orientation grains to the area of the crystal grains having crystal grain sizes not less than twice the average crystal grain size is not less than 50%.

Disclosed is a leadless free-cutting copper alloy that exhibits superior machinability, cold workability and dezincification resistance and a method for producing the same. The leadless free-cutting copper alloy comprises 56 to 77% by weight of copper (Cu), 0.1 to 3.0% by weight of manganese (Mn), 1.5 to 3.5% by weight of silicon (Si), and the balance of zinc (Zn) and other inevitable impurities, thus exhibiting superior eco-friendliness, machinability, cold workability and dezincification resistance.

Disclosed is a leadless free-cutting copper alloy that exhibits superior machinability, cold workability and dezincification resistance and a method for producing the same. The leadless free-cutting copper alloy comprises 56 to 77% by weight of copper (Cu), 0.1 to 3.0% by weight of manganese (Mn), 1.5 to 3.5% by weight of silicon (Si), and the balance of zinc (Zn) and other inevitable impurities, thus exhibiting superior eco-friendliness, machinability, cold workability and dezincification resistance.

A rolled copper foil for producing a two-dimensional hexagonal lattice compound, including P: 0.01 to 0.21 wt %, Fe: 0.006 wt % or less, and the balance being Cu and inevitable impurities, and having the following relationship: 2.0<=(I/I.sub.0) where I is a (111) diffraction intensity determined by an X ray diffraction of a rolled surface after heating at 1000° C. for 30 minutes and I.sub.0 is a (111) diffraction intensity determined by an X ray diffraction of fine powder copper.

A rolled copper foil for producing a two-dimensional hexagonal lattice compound, including P: 0.01 to 0.21 wt %, Fe: 0.006 wt % or less, and the balance being Cu and inevitable impurities, and having the following relationship: 2.0<=(I/I.sub.0) where I is a (111) diffraction intensity determined by an X ray diffraction of a rolled surface after heating at 1000° C. for 30 minutes and I.sub.0 is a (111) diffraction intensity determined by an X ray diffraction of fine powder copper.

There are provided a copper alloy for a slide bearing and a slide bearing, which can prevent Mn—Si primary crystals from causing seizure. The copper alloy for a slide bearing and a slide bearing according to the present invention contain 25 wt % or more and 48 wt % or less of Zn, 1 wt % or more and 7 wt % or less of Mn, 0.5 wt % or more and 3 wt % or less of Si, and 1 wt % or more and 10 wt % or less of Bi, the balance consisting of inevitable impurities and Cu, wherein there exist, in a sliding surface on which a counter material slides, Bi particles having a circle equivalent diameter larger than the average circle equivalent diameter of Mn—Si primary crystals and Bi particles having a circle equivalent diameter smaller than the average circle equivalent diameter of the Mn—Si primary crystals.