Microstructure Evolution During Al, Ti, and Mo Surface Deposition and Volume Diffusion in Ni-20Cr Wires and Woven Structures

Ni-20 wt pct Cr wires, as individual wires or within 3D woven structures, are alloyed with Mo, Al, and Ti by gas-phase surface deposition and volume interdiffusion. Mo deposition creates Mo-rich coating and Kirkendall pores. Al + Ti co-deposition creates uniform triple-layered coating. The resulting homogenized and aged Ni-(17.4-19.6) Cr-(1.6-1.8) Al-(2.5-3.6) Ti-(1.5-4.5) Mo(wt pct) wires exhibit gamma + gamma' superalloy microstructure. This demonstrates the feasibility of fabricating 3D woven Ni-base structures via gas-phase alloying and heat treatments, into multi-element superalloys with solid-state bonding at wire contacts. (C) The Minerals, Metals & Materials Society and ASM International 2015