An experimental study is presented on the wear and failure of VT6 alloy with a protective TiN coating in the initial coarse-grained and ultrafine-grained states, subjected to high-speed dynamic erosion by solid corundum particles with an average size of 109 μm in an air flow at a speed of 150 m/s and an exposure time of 30, 60, 180, 300 и 600 s. The experimental results were used to determine the erosive wear rate and the extent of ductile failure, as well as to measure the depth of the worn layer and changes in microhardness and structure of the alloy at the coated and uncoated erosion surface. It was shown that all alloy samples are prone to wear and failure under the given high-speed erosion conditions, but their behavior is closely related to the exposure time and the structure of the substrate. A protective coating deposited onto the surface of ultrafine-grained VT-6 titanium alloy significantly reduces the erosion wear rate compared to a similar coating on initial coarse-grained alloy.