A gas turbine engine, comprising: a core gas flow path; a secondary cooling flow path; and a gas turbine engine component, comprising: a component body (62, 64, 66) through which the core gas flow path extends; a radially-extending wall projecting from the component body into the secondary cooling flow path and fabricated from a parent material; one or more stress relief slots formed in the radially-extending wall and having respective interior surfaces; and a high temperature sealing material filling the one or more stress relief slots and impeding leakage between the secondary cooling flow path and the core gas flow path, the high temperature sealing material able to fracture in order to alleviate thermomechanical stress within the radially-extending wall during operation of the gas turbine engine characterized in that the high temperature sealing material is composed of a braze material having a mechanical strength less than the parent material and bonded to the interior surfaces of the one or more stress relief slots by disposing the braze material within said one or more stress relief slots and then subjecting it to a heat treatment to melt the braze material, thereby filling said one or more stress relief slots and forming bonds between the braze material and the interior surfaces of the stress relief slots. a core gas flow path; a secondary cooling flow path; and a gas turbine engine component, comprising: a component body (62, 64, 66) through which the core gas flow path extends; a radially-extending wall projecting from the component body into the secondary cooling flow path and fabricated from a parent material; one or more stress relief slots formed in the radially-extending wall and having respective interior surfaces; and a high temperature sealing material filling the one or more stress relief slots and impeding leakage between the secondary cooling flow path and the core gas flow path, the high temperature sealing material able to fracture in order to alleviate thermomechanical stress within the radially-extending wall during operation of the gas turbine engine characterized in that the high temperature sealing material is composed of a braze material having a mechanical strength less than the parent material and bonded to the interior surfaces of the one or more stress relief slots by disposing the braze material within said one or more stress relief slots and then subjecting it to a heat treatment to melt the braze material, thereby filling said one or more stress relief slots and forming bonds between the braze material and the interior surfaces of the stress relief slots. a component body (62, 64, 66) through which the core gas flow path extends; a radially-extending wall projecting from the component body into the secondary cooling flow path and fabricated from a parent material; one or more stress relief slots formed in the radially-extending wall and having respective interior surfaces; and a high temperature sealing material filling the one or more stress relief slots and impeding leakage between the secondary cooling flow path and the core gas flow path, the high temperature sealing material able to fracture in order to alleviate thermomechanical stress within the radially-extending wall during operation of the gas turbine engine characterized in that the high temperature sealing material is composed of a braze material having a mechanical strength less than the parent material and bonded to the interior surfaces of the one or more stress relief slots by disposing the braze material within said one or more stress relief slots and then subjecting it to a heat treatment to melt the braze material, thereby filling said one or more stress relief slots and forming bonds between the braze material and the interior surfaces of the stress relief slots.