Effect of H13 Dilution and Thermal Aging on Anviloy Wire Clad Microstructure
摘要
Tungsten heavy alloys such as Anviloy® 1150 offer superior die casting performance vs hot work tool steels, but high cost and processing difficulty limit applications. A new Anviloy alloy (60W–27.5Ni–12.5Fe) wire was developed for automated cladding and repair of die casting dies to improve affordability. A goal is to develop precision fusion welding technology for cladding key die components to improve die life. Prior to this study, there was an absence of Anviloy fusion welding metallurgy data. To develop Anviloy cladding technology, representative fusion zone deposit was prepared using arc crucible melting. Melt samples were prepared with three levels of H13 base metal dilution, 10, 20, and 30 pct. These samples were evaluated in as-cast and after thermal exposure at 600 °C and 725 °C for 100 hours. Optical microscopy, SEM backscatter imaging, and energy-dispersive spectroscopy were used to characterize the microstructure. 20 and 30 pct H13 dilutions produce a grain boundary M6C not seen in 10 pct dilution samples. Isothermal aging at 725 °C for 100 hours yielded high volume fraction of a new phase with needle-like morphology in 20 pct and 30 pct dilutions, but not 10 pct dilution. Calphad simulations indicated this phase was μ phase intermetallic, which was confirmed using TEM electron diffraction experiments.