EFFECT OF MOLYBDENUM ADDITION AND BETA HEAT TREATMENT ON HYDROGEN RESISTANCE OF ZIRCALOY 4-0.5Y AT 600°C AND 800 TEMPERATURES

• Main Author: NURFALAH, AJI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/62525
• Institution: Institut Teknologi Bandung

The development of electrical energy sources that are lower in carbon emissions is a concern at this time. Development of nuclear power plants is one of the concerns for energy sources with lower carbon emissions, including in the development of the efficiency and safety of nuclear power. One of the important components in a nuclear reactor is the fuel cladding which is the support for nuclear fuel. Zirconium alloys are the main material of choice for fuel cladding because of their corrosion resistance, low neutron absorption, and good mechanical properties. Zircaloy-4 is a zirconium alloy that is widely used as a fuel cladding. One of the failures that are often experienced by zirconium alloys is hydrogen embrittlement, where hydride formation occurs by hydrogen penetration from corrosion products which can reduce the mechanical properties of the alloy. This research was conducted to analyze the effect of adding molybdenum and beta heat treatment on hydrogen resistance and mechanical properties of zircaloy 4-0.5Y-xMo alloy (x=0; 0.1; 0.4 wt%). Research began with the manufacture of mixed alloys of zircaloy-4, Yttrium and Molybdenum which were melted and molded into buttons with various concentrations of molybdenum using a DC arc melting furnace. Then the button is cut into two parts and one of them is heat treated by heating at 1000 for 2 hours and then carried out water quenching is to form the ?-Zr phase. After that, the samples were hydrogen charged at temperatures of 600? and 800? for 5 hours using a mixture of argon and hydrogen gas in horizontal tube furnace. After hydrogen charging, the samples were characterized by conducting hardness tests, XRD tests, microstructures and SEM-EDS. The addition of molybdenum resulted in the refinement of the grain size and formation of intermetallic precipitate ZrMo2. Then it is known that the addition of molybdenum can increase the hardness and strength of the alloy. On the other hand, beta heat treatment causes the hardness of the alloy to decrease. Beta heat treatment can increase of hydogen resistance for Zircaloy 4-0,5Y-Mo alloy. Formation of ZrMo2 precipitates in the hydride layer on the addition of molybdenum has an influence on the hydrogen penetration behavior into alloy, intermetallic precipitates in the hydride layer cause faster hydrogen transport and faster hydration process. The addition of 0.1 wt% Mo to zircaloy 4-0.5Y alloy with beta heat treatment showed the best hydrogen resistance.