TZM material is a high temperature alloy which has a good oxidation resistance and good thermal conductivity. It is a common choice for applications that require repeated temperature cycling. In addition, it has excellent corrosion resistance. TZM material is commonly used in X-ray tubes, heat shields, horizontal posts, and load-bearing hearths.
TZM is produced using spark plasma sintering (SPS). The alloy contains 99.2% molybdenum, 0.50% titanium, 0.08% zirconium, and a trace of carbon for carbide formations. Compared to pure molybdenum, it has higher recrystallization temperature and higher hardness.
X-ray diffraction (XRD) was used to study the TZM microstructure. It was found that the rod grains had elongated cross-sections and became needle-like from the center to the edge. Several samples were analyzed for physiochemical and mechanical properties.
Tensile testing was conducted in ASTM E8. Tensile specimens were tested at 0.005 min-1 and a total of 1% error was allowed. Several reference tensile specimens were also machined from a TZM-1 rod. These were cut into half-circle cylindrical pieces and placed on graphite cloth.
The tensile tests showed that the samples did not fail brittle at room temperatures. However, a low-strain-rate ductile-to-brittle transition occurred at lower temperatures. This is an effect due to the MoO3 oxide layer that forms during dry sliding. A small spike in the Ti count occurs due to the presence of a TiC particle that is close to the interface.
To assess the impact of In on TZM, a series of tensile tests was performed. Small size tensile specimens were produced with a nominal diameter of 0.25 inch and a gauge length of one inch. Using the same TZM-1 rod, the samples were tensile-tested at 800 *C. The results were compared to those of the unexposed TZM sample.