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The evolution of the inhomogeneous distribution of the transformation stress (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>σ</mi><mi mathvariant="normal">s</mi></msub></mrow></semantics></math></inline-formula>) and strain fields with an increasing number of cycles in two differently orientated grains is investigated for the first time using a combined technique of digital image correlation and data-driven identification. The theoretical transformation strains (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>ε</mi><mi mathvariant="normal">T</mi></msub></mrow></semantics></math></inline-formula>) of these two grains with crystal orientations <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mrow><mo>[</mo><mrow><mn>5</mn><mo> </mo><mn>3</mn><mo> </mo><mn>26</mn></mrow><mo>]</mo></mrow></mrow><mi mathvariant="sans-serif">β</mi></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mrow><mo>[</mo><mrow><mn>6</mn><mo> </mo><mn>5</mn><mo> </mo><mn>11</mn></mrow><mo>]</mo></mrow></mrow><mi mathvariant="sans-serif">β</mi></msub></mrow></semantics></math></inline-formula> along the loading direction are 10.1% and 7.1%, respectively. The grain with lower <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>ε</mi><mi mathvariant="normal">T</mi></msub></mrow></semantics></math></inline-formula> has a higher <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>σ</mi><mi mathvariant="normal">s</mi></msub></mrow></semantics></math></inline-formula> initially and a faster decrease in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>σ</mi><mi mathvariant="normal">s</mi></msub></mrow></semantics></math></inline-formula> compared with the grain with higher <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>ε</mi><mi mathvariant="normal">T</mi></msub></mrow></semantics></math></inline-formula>. The results show that the grains with higher <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>σ</mi><mi mathvariant="normal">s</mi></msub></mrow></semantics></math></inline-formula> might trigger more dislocations during the martensite transformation, and thus result in greater residual strain and a larger decrease in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>σ</mi><mi mathvariant="normal">s</mi></msub></mrow></semantics></math></inline-formula> during subsequent cycles. Grain boundary kinking in bicrystal induces an additional decrease in transformation stress. We conclude that a grain with crystal orientation that has high transformation strain and low transformation stress (with respect to loading direction) will exhibit stable transformation stress, and thus lead to higher functional performance in Cu-based shape memory alloys.