We studied the entropy change and the shift of the martensitic transformation temperatures with magnetic field in samples of a polycrystalline Ni–Co–Mn–In alloy having different degrees of long-range atomic order due to different heat treatments. We found, for the samples of the same composition, strong variations of the entropy change with the degree of atomic order, mediated by the difference between the Curie and martensitic transformation temperatures. Calculations of the field-induced shift of the transformation using data of entropy variations show good agreement with experimental results.

Recent achievements have been analysed in designing and application of shape memory alloys as high-damping elements, utilizing pseudoelastic hysteresis, transient damping effects in the two-phase state and damping capacity of the martensitic phase.Dealing with intrinsic damping capacity of martensitic phases, several new observations are described, like 'universal' low-temperature high-damping properties of ternary Cu-based alloys, high non-linear damping capacity of a binary NiTi in R phase and high linear damping of binary hydrogen-charged NiTi. Based on the analysis of results of recent studies of damping in NiTi (B19 martensite, R phase) and Cu-based families of alloys (Cu-Al-Ni, Cu-Zn-Al, Cu-Al-Be), we try to introduce a guideline relating desired damping properties of a SMA with its structural characteristics. Among the parameters determining the contribution of specific defect species to damping we suggest considering• density of specific type of defects (intervariant boundaries and internal defects of variants like dislocations and twins); • their mobility (determined by crystallography and geometrical factors, like accommodation and size of martensitic variants); • concentration and type of obstacles impeding the motion of defect species and, thus, producing damping (concentration, mobility and distribution of quenched-in/point-like defects, precipitates, etc).The importance of distinguishing linear and non-linear components of damping is emphasized, since, in a general case, they can be related to different elements of defect microstructure of martensite.

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Due to unique functional and mechanical properties, NiTi shape memory alloys are one of the most promising metallic functional materials. However, the poor workability limits the extensive utilization of NiTi alloys as components of complex shapes. The emerging additive manufacturing techniques provide high degrees of freedom to fabricate complex structures. A freeform fabrication of complex structures by additive manufacturing combined with the unique functional properties (e.g., shape memory effect and superelasticity) provide great potential for material and structure design, and thus should lead to numerous applications. In this review, the unique microstructure that is generated by selective laser melting (SLM) is discussed first. Afterwards, the previously reported transformation behavior and mechanical properties of NiTi alloys produced under various SLM conditions are summarized.