Abstract: The present invention provides an artifactless superelastic alloy including a Au—Cu—Al alloy, the superelastic alloy containing Cu in an amount of 20 atom % or more and 40 atom % or less, Al in an amount of 15 atom % or more and 25 atom % or less, and Au as a balance, the superelastic alloy having a bulk magnetic susceptibility of ?24 ppm or more and 6 ppm or less. The Ni-free superelastic alloy of the present invention is capable of exhibiting superelasticity in a normal temperature range, and hardly generated artifacts in a magnetic field environment. The alloy can be produced by setting a casting time in a melting and casting step to a fixed time, and hot-pressing an alloy after casting to make material structures homogeneous.

Abstract: The present invention provides a shape-memory alloy including a Au—Cu—Al alloy having 20 at % or more and 40 at % or less Cu and 15 at % or more and 30 at % or less Al, with the balance being Au and inevitable impurities. The shape-memory alloy has a Vickers hardness of 360 Hv or less. The Au—Cu—Al alloy of the present invention is an alloy capable of developing both biocompatibility and a shape-memory effect, and further capable of achieving artifactlessness in a magnetic environment. The Au—Cu—Al alloy can be produced by heat-treating a clad material formed of a combination of a hollow material made of a Au—Cu alloy and a core material made of metallic Al at 500° C. or more and 700° C. or less.

Abstract: The present invention provides an artifactless superelastic alloy including a Au—Cu—Al alloy, the superelastic alloy containing Cu in an amount of 20 atom % or more and 40 atom % or less, Al in an amount of 15 atom % or more and 25 atom % or less, and Au as a balance, the superelastic alloy having a bulk magnetic susceptibility of ?24 ppm or more and 6 ppm or less. The Ni-free superelastic alloy of the present invention is capable of exhibiting superelasticity in a normal temperature range, and hardly generated artifacts in a magnetic field environment. The alloy can be produced by setting a casting time in a melting and casting step to a fixed time, and hot-pressing an alloy after casting to make material structures homogeneous.

Abstract: The present invention provides a superelastic alloy formed by addition of Fe or Co to an Au—Cu—Al alloy, including: Cu of 12.5% by mass or more and 16.5% by mass or less; Al of 3.0% by mass or more and 5.5% by mass or less; Fe or Co of 0.01% by mass or more and 2.0% by mass or less; and a balance Au, and a difference between Al content and Cu content (Cu—Al) is 12% by mass or less. The superelastic alloy according to the present invention has superelastic property while being Ni-free, excellent X-ray imaging property, processability, and strength property, and is suitable for a medical field.

Abstract: The present invention provides a superelastic alloy formed by addition of Fe or Co to an Au—Cu—Al alloy, including: Cu of 12.5% by mass or more and 16.5% by mass or less; Al of 3.0% by mass or more and 5.5% by mass or less; Fe or Co of 0.01% by mass or more and 2.0% by mass or less; and a balance Au, and a difference between Al content and Cu content (Cu—Al) is 12% by mass or less. The superelastic alloy according to the present invention has superelastic property while being Ni-free, excellent X-ray imaging property, processability, and strength property, and is suitable for a medical field.