Cast in situ composites of Ni3Al / MeC type
Journal Title: Archiwum Odlewnictwa - Year 2009, Vol 9, Issue 2
Abstract
In this work a new method SHSB (Self- Propagating High-Temperature Synthesis in Bath) has been used to produce of five new composites i.e.Ni3Al / TiC, Ni3Al / WC, Ni3Al / Zr, Ni3Al / NbC and Ni3Al /TaC (in the amount of carbides of 5% volume fraction.) The composites fabricated by the „in situ” process, with the Ni3Al compound used as a matrix material and the reinforcement composed of Ti, W, Zr, Nb or Ta carbide particles were made. Fabrication of composites was carried out in Balzers vacuum furnace and conducted the process in the atmosphere of argon at a negative gas pressure of 0,5 MPa. After melting down of aluminium and completion of the exothermic reaction between mixing powder of carbon, aluminium, titanium or tungsten, zirconium, niobium and tantalum, boron in the form of Al-B 3% master alloy was introduced to alloy melt. From thus fabricated composites, the specimens were prepared for metallographic examinations, and scanning topographic analysis. It have been shown that the size of TiC and TaC particles was comprised in a range of up to 10 μm. The NbC and ZrC carbides were characterised by the dimensions of up to 20 μm, while WC carbides were the largest (up to 80 μm.) In all the examined composites, the X-ray microanalysis revealed total absence of reaction products at the matrixreinforcing particle interface. The SHSB process eliminated the fundamental problem - reactivity of the matrix-particle system, observed in the ex situ methods .
Authors and Affiliations
E. Fraś, A. Janas
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