PROBLEM TO BE SOLVED: To provide a low-elasticity titanium alloy for a bioimplant consisting of inexpensive metal elements abundant as resources and devoid of biotoxicity.SOLUTION: The low-elasticity titanium alloy of the present invention comprises: at least 4.0% and no more than 6.0% of Cr at least 5.0% and no more than 9.0% of Sn and more than 0% and no more than 40% of Zr and has a balance consisting of Ti and inevitable impurities, is applied to bones of living subjects, and has a Youngs modulus lower than 60 GPa. A prescription including, in terms of mass%, at least 3.0% and less than 4.0% of Cr, at least 5.0% and no more than 9.0% of Sn, and at least 10% and no more than 30% of Zr or at least 1.0% and less than 3.0% of Cr, at least 5.0% and no more than 9.0% of Sn, and at least 30% and no more than 40% of Zr is also permissible. Moreover, a prescription including, in terms of mass%, at least 7.0% and no more than 9.0% of Cr and at least 3.0% and no more than 6.0% of Al is also permissible.COPYRIGHT: (C)2015,JPO&INPIT【課題】生体への毒性が無くかつ廉価で資源豊富な金属元素からなる生体インプラント用の低弾性チタン合金を提供する。【解決手段】本発明の低弾性チタン合金は、Crを4.0%以上6.0%以下、Snを5.0%以上9.0%以下、Zrを0%より大きく40%以下となる範囲で含有し、残部がTi及び不可避的不純物からなり、生体の骨に適用され、かつ、ヤング率が60GPa未満であることを特徴とする。また、質量%で、Crを3.0%以上4.0%未満、Snを5.0%以上9.0%以下、Zrを10%以上30%以下となる範囲で含有するものや、Crを1.0%以上3.0%未満、Snを5.0%以上9.0%以下、Zrを30%以上40%以下となる範囲で含有するものでもよい。さらに、質量%で、Crを7.0%以上9.0%以下、Alを3.0%以上6.0%以下となる範囲で含有するものでもよい。【選択図】図3
