Extreme environment corrosion evaluation method and clamp under gap and stress coupling effect

The invention relates to an extreme environment corrosion evaluation method and clamp under a gap and stress coupling effect. The method comprises the following steps: a, preparing a simulated corrosion solution, and removing oxygen in the simulated corrosion solution; b, removing oil from the sample, dehydrating and drying; c, enabling the sample to penetrate through two through holes in the E-shaped part of the clamp and to be fixed on the stress four-point bend, and enabling the stress of the stress four-point bend to be 100% yield strength; d, pouring the simulated corrosion solution intoa reaction kettle, completely immersing the sample, deoxidizing and heating the solution, and introducing a corrosion medium into the reaction kettle for corrosion; e, after corrosion is finished, taking out the sample, removing a corrosion product on the surface of the sample, and then cleaning and drying the sample; f, performing corrosion failure analysis, observing the surface corrosion condition of the sample, and ev