1 research outputs found
Estimation of fatigue strength of TiN coatings using cyclic micro-impact testing
This study delves into the behaviour of a thin TiN coating on a tool steel
substrate material under dynamic and cyclic impacts through a comprehensive
approach combining experimental testing and computational modelling. In dynamic
impact tests, a pendulumbased setup investigates material responses under
varying acceleration loads, revealing a distinctive "ringing effect" as the
indenter bounces off the specimen's surface, with all plastic deformation
concentrated during the initial impact. The study also quantifies dynamic
hardness values, highlighting load-dependent behaviour and assessing the
coating system's energy dissipation capabilities. In cyclic impact tests,
materials experience permanent plastic deformation with each cycle, ultimately
leading to coating failure. Chemical analysis identifies an interlayer between
the coating and substrate, while cross-sectional analysis reveals the extent of
coating damage due to cycling and load. A three-dimensional map is constructed,
connecting acceleration load, sensed depth, and cycles to coating failure, and
an empirical equation characterizes the relationship between depth and cycles
before failure. The computational model scrutinizes traction component
distribution during loading and unloading, with a focus on normal and shear
tractions. The findings suggest the potential significance of normal traction
in interface fatigue failure. Overall, offering implications for understanding
and mitigating fatigue-related failures across various applications