Exploration of the Microstructure Space in TiAlZrN Ultra-Hard Nanostructured Coatings

Vahid Attari; Aitor Cruzado; Raymundo Arroyave

doi:10.1016/j.actamat.2019.05.047

paper

Exploration of the Microstructure Space in TiAlZrN Ultra-Hard Nanostructured Coatings

arXiv:1811.05017 · doi:10.1016/j.actamat.2019.05.047

Abstract

Ti $_{1 - x - y}$ Al $_{x}$ Zr $_{y}$ N cubic alloys within the 25-70\% Al composition range have high age-hardening capabilities due to metastable phase transition pathways at high temperatures. They are thus ideal candidates for ultra-hard nano-coating materials. There is growing evidence that this effect is associated with the elasto-chemical field-induced phase separation into compositionally-segregated nanocrystaline nitride phases. Here, we studied the microstructural evolution in this pseudo-ternary system within spinodal regions at 1200 $^{\circ}$ C by using an elasto-chemical phase field model. Our simulations indicate that elastic interactions between nitride nano-domains greatly affect not only the morphology of the microstructure but also the local chemical phase equilibria. In Al-rich regions of the composition space we further observe the onset of the transformation of AlN-rich phases into their equilibrium wurtzite crystal structure. This work points to a wide palette of microstructures potentially accessible to these nitride systems and their tailoring is likely to result in significant improvements in the performance of transition metal nitride-based coating materials.

Exploration of the Microstructure Space in TiAlZrN Ultra-Hard Nanostructured Coatings

Abstract

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