Improvement of mechanical property and large shape recovery of sintered Ni45Mn36.6In13.4Co5 alloy

High mechanical properties Ni45Mn36.6In13.4Co5 magnetic shape memory alloy with preferred orientation were prepared by spark plasma sintering melt-spinning ribbons piled up orderly. Sintered at 1073 K, the orientation of grains becomes random. Sintered at 873 K, part of the grains grows inhomogeneously and some of the columnar grains are fractured under relatively large compressive pressure. Mechanical properties of Ni-Mn-In-Co alloy are improved significantly by spark plasma sintering the ribbons. The compressive fracture strength and strain of the Ni45Mn36.6In13.4Co5 bulks sintered at 873 K are 1200 MPa and 14%, which are approximately two times larger than that of ingots as-cast. The improvement of mechanical property can be attributed to the textured microstructure and relatively tiny grains in sintering ingots. It must be mentioned that the alloys sintered at 873 K show almost perfect shape memory effect, about 95% compressive strains (as high as 11.4%) was recoverable during heating, and shape recovery is achieved in reverse martensitic transformation process, which predicts a relatively high magnetic field induced strain recovery in polycrystalline.