Method for preparing coarse-grain iron manganese silicon based shape memory alloy

Abstract

The invention discloses a method for preparing coarse-grain iron manganese silicon based shape memory alloy, and belongs to the field of shape memory alloy. The average size of austenite grains of theiron manganese silicon based shape memory alloy prepared through the method is larger than or equal to 1 mm. The method includes the specific steps that (1) the iron manganese silicon based shape memory alloy is treated at the temperature of 1260-1300 DEG C for 5 min to 1 h; (2) the following treatment process is repeated at least once: the iron manganese silicon based shape memory alloy is cooled to 1100-1200 DEG C with the speed of 0.1-10 DEG C / min and treated for 5-30 min, and then the iron manganese silicon based shape memory alloy is heated to 1260-1300 DEG C with the speed of 0.1-10 DEGC / min and treated for 5 min to 1 h; and (3) finally, the iron manganese silicon based shape memory alloy is cooled to 1150-1200 DEG C with the speed of 0.1-5 DEG C / min, and then subjected to water cooling to the room temperature.

Description

technical field [0001] The invention relates to the field of shape memory alloys, in particular to a method for preparing iron-manganese-silicon-based shape memory alloys with coarse austenite grains. The average austenite grain size of the iron-manganese-silicon-based shape memory alloy prepared by the method is not less than 1 mm. Background technique [0002] Iron-manganese-silicon-based alloy has the advantages of low cost, easy processing and good welding performance, so it has attracted extensive attention of scholars at home and abroad since its discovery. However, the recoverable strain of the polycrystalline Fe-Mn-Si-based alloy deformed without special treatment (hot rolling, cold rolling or cold drawing) is only about 2%, which cannot meet the requirements of engineering applications. At present, the three methods of training (repeated process of deformation at room temperature and annealing around 650°C), high-temperature deformation heat treatment of austenite ...

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Problems solved by technology

However, the current method of coarsening austenite grains is mainly to increase the solution treatment temperature and prolong the solution treatment time.

However, due to the low stacking fault energy of iron-manganese-silicon-based alloys, annealing twins are easy to form, which makes the above method unable to effectively increase austenite grains (H.B. Peng, et al.. Materials Science and Engineering A, 2018, 712: 37-49)