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The use of micro selective laser melting (μ-SLM) enables product miniaturization, which is one of the megatrends in the metal processing industry and increasingly find its applications in biomedical and electronics industries. Among these, NiTi shape memory alloy (SMA) shows a great promise in functional micro-scaled components such as stent. There are inevitably some imperfections in SLM, but the imperfection formation in μ-SLM may not be the same as that in the conventional SLM. This work studies the imperfections in μ-SLM produced NiTi samples, with focus on defects, microstructure and thermal/mechanical behaviors. The effects of substrate material, laser-related process parameter and scanning strategy on defects such as porosity and cracks were analyzed, and a process window for “Scanning speed – Hatch spacing” was determined. Transformation peak was hardly detected in thermal behavior of as …