Publication

Abstract : TiAlN and AlCrN coating has been deposited on MDC-K hot work tool steel by PVD technique. The microstructure, elemental composition, nanomechanical and wear properties of bare nitrided and coated surface were evaluated using XRD, Raman spectroscopy, FE-SEM along with EDS, nanoindentation and nanoscratch test. AFM have showed improvement in surface with reduction in friction coefficient by ∼47.62% and ∼45.71% with TiAlN and AlCrN coating respectively. The mechanical properties of MDC-K tool steel substrate such as hardness, elastic modulus and strain hardening exponent got improved post coating wherein TiAlN coating had exhibited higher wear resistance (H/E), improved plastics deformation resistance (H3/E2), high scratch hardness and lower specific wear rate compared to AlCrN coating. This led to lower pile up and plastic deformation in TiAlN coating. In addition to this, wear behavior of bare nitrided, TiAlN and AlCrN coated surface were evaluated under different tribological conditions. Bare nitrided surface worn out due to abrasive wear mechanism whereas AlCrN coating exhibited both smooth and rough surface due to adhesive and abrasive wear mechanism. Furthermore, TiAlN coated surface exhibited lower specific wear rate and superior micro-hardness compare to bare nitrided and AlCrN coated surface post tribotests.