Ahmed S. Technological basis of production of castings from alloys with shape memory effect on the iron-based with increased mechanical and operational properties

This thesis is devoted to solution of important scientific and practical task of obtaining new alloys with shape memory effect, which allows to simplify and cheapen the technology of obtaining these alloys while ensuring high values of their operational properties. Analysis has shown that the known iron-based alloys with shape memory effect (SME) have a number of unsolved problems. The obtained alloy with a justified chemical composition, which is a high-alloyed austenitic chromium steel with carbide hardening. The technological process of obtaining an iron-based alloy with a shape memory effect, which is a austenitic manganese steel, is investigated. The choice of the chemical composition of the alloy is justified, the heat treatment modes are selected. It is established that the hardening heat treatment of the proposed alloy can significantly increase the strength characteristics (up to 1380 MPa) and at the same time increase the value of the SME (up to 97%). It is shown that, in the proposed alloy, the values of the shape memory effect, which was characterized by the angles of extension of the samples, have rather high values (125-160 °). The proposed iron-based alloys with shape memory effect can be obtained both in laboratory conditions and on industrial equipment. The approbation of the developed alloy was carried out - an improved technological process was developed for the restoration of cast body parts based on the use of a repair sleeve with shape memory effect. The practical significance of the obtained results is confirmed by the implementation of the proposed methods and approaches in the development and in the educational process.