Numerical Simulation Of High Temperature Compression And Cyclic Deformation Of Porous Cu-35Ni-15Cr For Molten Carbonate Fuel Cell

Melt carbonate fuel cell(MCFC)is a kind of high-temperature fuel cell with high efficiency and environment-friendly and it has been extensively researched.It has high requirements for the anode material,such as high electrical conductivity,high structural strength etc.Due to the material and its high price,Ni dissolve easily in the electrolyte and it is easy to migrate and precipitate near the anode,the traditional Ni alloy finally may lead to battery short circuit,and it is prone to creep and fatigue at high temperature and battery assembly pressure.Because of excellent electrical conductivity,antioxidant properties,good anti-creep performance,and lower cost than Ni,Porous Cu alloy is an ideal material for MCFC that can replace Ni alloys.In the dissertation,several porous Cu-35Ni-15Cr alloy materials with different porosities were prepared by the traditional process,and the high temperature compression and cyclic deformation behavior of these materials were simulated.(1)The porous Cu-35Ni-15Cr alloy was prepared by adding pore-forming agent and pressing method,and the porosity was controlled by changing the amount of pore-forming agent.After removal of the pore-forming agent,the sample was sintered at high temperature,and a batch of porous Cu-35Ni-15Cr alloy with a porosity of 60%and a minimum of 38%was obtained.(2)The numerical simulation of Cu-35Ni-15Cr alloy with porosity of 40%was carried out by using ABAQUS finite element software.And the stress-strain curve obtained from the simulation was compared with the experiment,the two curves are basically consistent.In the yield stage,the simulation curve is slightly higher than the experimental curve.The reason is that the material is assumed in the numerical simulation,and the distribution of holes and the defects is not considered.At the same time,the numerical simulation of different structural parameters(porosity and pore size)at 650? was carried out.The results showed that the porosity and pore size have an important effect on the compressive mechanical behavior of porous materials.The porosity and pore size are large,its elastic modulus and the yield strength are lower.(3)The cyclic deformation behavior of the porous Cu-35Ni-15Cr alloy was simulated,and the evolution curve of the hysteresis loop and its ratchet strain with time were obtained.The conclusion was similar to that of the multi-master.The effects of different loading conditions(stress ratio,loading amplitude,average stress)and different structural parameters(porosity,pore size)on the ratcheting behavior of porous copper alloy were discussed.The simulation results show that the ratcheting strain increases with the increases of the stress ratio,the loading amplitude and the average stress in the case of a single factor.And it indicates that it has an important effect on the ratcheting behavior of the porous material.At the same time,it is concluded that the increase of porosity and pore size will make the ratcheting behavior of porous copper alloy material more obvious and weaken the ability of material to resist deformation.