Mechanochemical method of fatigue crack growth arrest in metals by its artificial closure

A method based on supplying a special liquid technological environment containing tannins into the crack cavity is investigated, which leads to the intensive formation of insoluble tannats in it. The compounds, filling the crack cavity, create an essential crack closure effect in the steel up to its complete arrest in a wide range of stress intensity factors. Alloys with different corrosion resistance are studied: carbon steel 20, 12Kh18N10Т stainless steel, and VT1‑0 titanium. The effectiveness of the method is estimated based on fatigue crack growth curves. A crucial role of crack closure in its arrest is confirmed. The unequal effectiveness of the method for various metal materials is shown. This is explained by the competitive formation of oxide films, which prevent the accumulation of tannate deposits in the crack.