METHOD FOR PRODUCING TOUGH IRON-BASE SHAPE MEMORY ALLOY

摘要

PROBLEM TO BE SOLVED: To provide a method for most effectively toughening an iron-base shape memory alloy basically containing Fe, Mn, Si as a practical material, having the simplest component constitution.;SOLUTION: This alloy contains, by weight, 15-40% Mn, 3.5-8.0% Si and the balance Fe as the basic components, and Cu limited to the concentration, in which slender ε-Cu phase is not precipitated along γ-austenite crystal grain boundary. After solidifying and forming, a solution treatment is applied to the solid-solution temperature of the segregated and concentrated Mn and Si precipitation into the γ-austenite phase and thereafter, this alloy is quickly cooled from the temperature and a part of supersaturated solid-solution of Cu is finely precipitated in the crystal grain, and hardened to solve the above problem. When Cu in the γ-phase forms a substitutional solid-solution, the strain is developed in the network of nearby crystal lattice, and slippage along the atomic plane hardly occurs and also, Cu-phase is finely precipitated and the hardening is developed and then, the mechanical properties, particularly, the durability and the elongation are improved.;COPYRIGHT: (C)2005,JPO&NCIPI