The Tensile Properties, Scratch Behaviors and Sliding Wear of Oxide Scale Formed on Titanium Grade 2

Abstract

<jats:p>The tensile properties, scratch behaviors and sliding wear of an oxide scale obtained on the surface of titanium Grade 2 in the process of isothermal oxidation at 600, 700 and 800 °C were determined in the study. It was shown that the intensity of the oxidation process increased along with an increase in temperature and extension of the oxidation time, which translated directly into the thickness of the deposited oxide layers. The tests showed that isothermal oxidation had an adverse effect on the tensile properties of titanium. After oxidation, it was found that the maximum reduction in tensile strength, Rm, was approximately 17.5%, and of the yield point, Rp0.2, approximately 13.9%. Examination of scratch behaviors of the oxide scale showed that the layers obtained at temperatures of 700 (72 h) and 800 °C (2 and 6 h) had the best adhesion properties. The best resistance to scratching was exhibited by the layer obtained after 6 h oxidation at 800 °C (critical load: Lc1 = 63 N, Lc2 = 85 N). The study showed that after oxidation, a considerable reduction in wear factor of a disc made of titanium Grade 2 was observed for both the friction couples used (Al2O3, steel 100Cr6). The maximum reduction in wear factor of the oxidized titanium disc during interaction with Al2O3 balls was ca. 79%, and with 100Cr6 balls, ca. 96%.</jats:p>

Effect of oxide layers formed by thermal oxidation on mechanical properties and NaCl-induced hot corrosion behavior of TC21 Ti-alloy

“…Improved wear characteristics are attributed to limiting deformation in the top oxide layer and the lowering of www.nature.com/scientificreports/ shear strength 8 . According to the Archard rule, wear rate is inversely proportional to material hardness, which indicates that the rise of material hardness increases wear resistance 11 . The surface morphologies, composition, and hardness of the oxides formed at 900 °C led to spallation of the oxide layer and reduced the layer adhesion, affecting the wear rate.…”

“…The disadvantage of this technique is the flaking of the oxide layer at high temperatures. When the thickness of the formed layer increases, it cracks and spalls due to the stresses caused by the difference in thermal expansion between the formed oxide layer and the base metal 11 . Ti alloy has been alloyed with numerous elements (such as Al, Mo, Nb, Zr) to enhance the alloy properties at higher temperatures 12 ; notably, their oxidation resistance compared to steels and nickel-based alloys.…”

Effect of oxide layers formed by thermal oxidation on mechanical properties and NaCl-induced hot corrosion behavior of TC21 Ti-alloy

“…According to the Archard rule, wear resistance is may be related to the material hardness. That indicates that the hardness of the material rises with the wear resistance increasing 12 .…”

“…The disadvantage of this technique is the aking of a layer at high temperatures. Due to the difference in thermal expansion, when the thickness of the formed layer increases, it cracks and spalls 12 . Ti alloy has been added with numerous elements (such as Al, Mo, Nb, Zr) to increase the behavior of its alloys at increased temperatures 13 , notably their oxidation resistance, comparable to steels and nickel-based alloys.…”