Abstract: Most inorganic thermoelectric semiconductors are intrinsically brittle, restricting the application of thermoelectric materials. Therefore, developing ductile thermoelectric materials is crucial to thermoelectric technology applications. In this work, single-phase SnTe bulks with dense dislocations were prepared by melting quenching combined with spark plasma sintering. The resulting SnTe thermoelectric materials exhibited a large compressive strain of ∼7.5% at room temperature, originating from high-density pre-existing mobile dislocations. The initiation of localized slip bands and preferred slip system were also identified by first-principles simulation. Detail microstructural characterizations reveal that the thermal activated dislocation emission and migration lead to higher compressive strains at intermediate temperatures. At 673 K, the deformation mechanism changed from dislocation mediated to grain boundary mediated plasticity, resulting in an ultra-high compressive strain of ∼42%. In sum, new insights into the mechanical behavior of SnTe thermoelectric material over a wide range of temperatures were provided. This work offers the dislocation engineering strategy to design ductile thermoelectric materials for flexible electronics and energy systems.

Key words: SnTe, Ductile thermoelectric materials, Deformation mechanism, Dislocation engineering