2017 | AFC ACCOMPLISHMENTS 168 Accomplishments: (1) Completion of comprehensive thermodynamics simulation on the formation and composition of equilibrium phases in the proposed TMP conditions is the first main achievement for the processing development scope in FY 2017. The calculated phase diagrams for HT9 alloys show that the M23C6 carbide, Sigma, Laves, and body centered cubic (BCC) phases form in the low-temperature region at < ~800°C. Fe and Cr are the major elements within face centered cubic (FCC) phases above the upper transformation temperature (A3) (~880°C). Small amounts of FCC phases remain at lower temperatures.The temperature- dependent compositions within individual phases also comprise key reference data for the processing development. Figure 1, for example, displays the temperature dependent stabilities of various M23C6 carbides, showing that the most stable or major phase is Cr20Mo3C6.The Figure 2. Temperature dependence of yield strength (YS) in HT9 steels with and without nitrogen doping (4 and 3 series, respectively, in the legend) after pre-tempering at 300–600°C and final tempering (750°C) treatments, which are compared with the YS data after water quenching (WQ) and 750°C tempering only.