残余应力对固体氧化物燃料电池弹塑性性能的影响

摘要

Due to the differences of Young's modulus and the mismatch of thermal expansion coefficients in the half-cell structure (NiO-YSZ/YSZ), the residual stress, which has effects on the fuel cell's performance, is aroused during sintering. Taking the residual stress into consideration, a modified reverse analysis model was proposed to calculate the mechanical property of electrolyte thin film in SOFC. Nanoindentation tests were carried out at the points with difference distances from the interface of bilayer, the load-displacement curve was presented. The results of material's mechanical property from experimental showed that the farther the indentation points was from the interface, the greater was the hardness of film. When the temperature related residual stress field was taken as the initial stress field to simulate the load-displacement curve under nanoindentation, it was found that the load-displacement curve was in agreement with the experiment curve if the residual stress was considered, and also the indentation morphology was much deeper and bigger under the residual stress condition.%半电池结构NiO-YSZ/YSZ由于弹性模量不同和热膨胀系数不匹配,导致烧结过程中产生残余应力.残余应力对于燃料电池的性能和使用带来一定的影响,本文把残余应力引入到计算薄膜性能的逆向分析模型中,建立了考虑残余应力影响的薄膜的纳米压痕分析模型.利用纳米压痕方法测试了离双层材料界面不同距离处的载荷-位移曲线和相应的材料性能,用本文建立的模型计算了不同点的性能的变化,发现离界面越远,电解质YSZ薄膜的硬度越大.将热力分析得到的残余应力场作为压痕模拟的初始应力场,计算三棱锥压头下压痕载荷-位移曲线,结果显示考虑残余应力时的载荷-位移曲线更接近实验曲线,并给出了残余应力下压痕形貌图,发现有残余应力时的压痕形貌更深更大.