Abstract:The microstructural characteristics and thermal stress relaxation of ZrO₂-Ni functionally gradient materials (FGM) by hot-pressing were studied. The investigation by scanning and transmission electron microscopy as well as X-ray diffractometry demonstrated that the chemical composition and microstructure of ZrO₂-Ni FGM distributed gradiently in stepwise way. The constituents, both zirconia and nickel, were continuous in microstructure everywhere, eliminating the macroscopic interface in traditional ceramics/metal joint. By means of finite element method, the thermal stress distribution in a layered ZrO₂/Ni material (nonFGM) and that in a ZrO₂-Ni FGM under an analogical condition with great temperature difference were preliminarily analyzed. It was shown that the thermal stress value in ZrO₂-Ni FGM remarkably decreased and distributed more smoothly in comparison with that in ZrO₂/Ni non-FGM. Obviously the ZrO₂-Ni FGM has the function of thermal stress relaxation.

Key words: functionally graded material　zirconia　nickel　microstructure　thermal stress relaxation