Fig. 1 a LMD TA15 component; b direction of specimens extracted from the bulk component; c size and dimensions of the in-situ tensile testing sample

Fig. 2 a Schematic of the SEM chamber with high temperature in-situ tensile testing set-up; b view of the tensile stage with heating core

Fig. 3 As built characteristics of the alloy: a XRD patterns; b OM image showing the columnar β-grain; c SEM low magnification surface view showing prior β GB and parallel α colony along prior β GB; d magnified image showing basketweave α appearance

Fig. 4 Force-displacement curves of the specimen at room temperature and 500 °C (Curves III and IV showing the in-situ process acquisition stages)

Fig. 5 In-situ tensile deformation process of Z-direction specimen at 500 °C at a displacement of a 763 µm, b 970 µm, and c 985 µm; d fracture morphology of the specimen. The tensile direction was applied horizontally

Fig. 6 Microstructure evolution during in-situ tensile deformation of Z-direction specimen at 500 °C at a displacement of: a 653 µm, b 763 µm, c 866 µm, d 970 µm

Fig. 7 In-situ tensile deformation process of X-direction specimen at 500 °C: a before tensile deformation showing layer interface and prior β GB orientation, b deformation at displacement of 784 µm, c deformation at displacement of 842 µm, d fracture failure, e enlarged encircled part showing the trace of prior β GB, f fracture surface morphology. Loading direction was applied horizontal

Fig. 8 Microstructure variation of X-direction sample during in-situ tensile deformation at temperature of 500 °C: a slip bands along β GB at a displacement of 657 µm, b intergranular slips at a displacement of 657 μm, c slips pile-up at a displacement of 784 µm, d slips hindrance by GB at a displacement of 784 µm, e microcracks accumulation at displacement of 842 µm, f fracture failure. Inset in a: TD-tensile direction, BD-building direction

Fig. 9 SEM micrographs illustrating impact of grain boundaries on deformation process: a Z-direction specimen at a displacement of 866 µm, b X-direction specimen at a displacement of 784 µm. Schematic of the deformation mechanism at 500 °C: c Z-direction specimen, d X-direction specimen

Fig. 10 SEM micrographs showing: a uniform movement of slip bands and microcracks fusion in Z-direction, at a displacement of 970 µm (close to fracture failure), b resistance to slip bands and microcracks by misoriented grain in X-direction specimen, at a displacement of 842 µm (close to fracture failure)