High strength and toughness of in-situ TiC/In718 functionally gradient material by using Ti3AlC2 as a precursor

In this work, the Inconel 718 functionally gradient material(In718 FGM) with different TiC contents was fabricated successfully by in situ hot-press reaction. Its microstructural characteristics, phase evolution and room temperature mechanical performance were analyzed. The paper considers the effects of micro-structure on crack propagation and toughening mechanism. The results show that the fabricated gradient material was compact and had no such defects as cracks and delamination. The metal matrix presented a streamlined and equiaxed structure, due to the uniform distribution of in situ ultrafine TiC transformed from Ti3AlC2 in the matrix. The overall performance of In718 FGM was thus improved. The Vicker's hardness presented linear distribution along gradient direction, and the surface hardness reached 591HV1, ap-proximately two times greater than that of the monolithic In718 matrix. Meanwhile, the overall fracture toughness and the flexural strength of FGM reached 60.44 MPa.m(1/2) and 2141 +/- 46 MPa, increased by 15% and 10%, respectively. With high hardness, high strength and toughness, therefore, the fabricated FGM formed a structure of hard outside and tough inside. (C) 2022 Published by Elsevier B.V.