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In the present paper we use nanoindentation to investigate two shape memory alloys, austenitic Ti₅₀Ni₄₈Fe₂ and martensitic Ti₅₀Ni₄₀Cu₁₀ which both show two step martensitic transformations on cooling from the high temperature regime. No such two step features were observed during nanoindentation. Load controlled nanoindentation experiments were performed using a Berkovich indenter using maximum loads ranging from 0.5 to 85 mN resulting in maximum indentation depths between 30 and 1350 nm. For small maximum indentation loads below 5 mN, longer indentation times result in larger indentation depths (austenitic Ti₅₀Ni₄₈Fe₂). At loads of about 1 mN the indentation curves show an abrupt change in slope which we suggest to be related to an interaction of the deformation and failure of a thin oxide layer and the formation of stress induced martensite (austenitic Ti₅₀Ni₄₈Fe₂) or the de-twinning of martensite (martensitic Ti₅₀Ni₄₀Cu₁₀). Nanohardnesses and shape recovery ratios strongly increase with decreasing indentation depths below 400 nm. For larger indentation depths, constant values are observed (austenitic Ti₅₀Ni₄₈Fe₂: nanohardness 2.45 GPa/recovery ratio 0.25, martensitic Ti₅₀Ni₄₀Cu₁₀: nanohardness 1.6 GPa/recovery ratio 0.4).