论文部分内容阅读
研究了沉淀强化奥氏体不锈钢J75经受不同温度热冲击及一定温度下多次热冲击作用后的力学性能变化规律,并探索了性能损伤机理.研究结果表明,在作用时间为1s的情况下,温度低于610℃,单次或多次热冲击对合金的力学性能无明显损伤;温度高于750℃;热冲击明显影响合金的力学性能,强度和延伸率都随热冲击次数增加明显降低.显微分析表明,热冲击温度和热冲击次数的增加,促进了晶粒细化,也使材料的析出相发生了明显的变化.在高于750℃下产生的大量片状η相的析出及γ强化相的粗化和不均匀分布,是引起J75不锈钢强度和延伸率显著下降的主要原因.
The variation of mechanical properties of precipitation-strengthened austenitic stainless steel J75 subjected to thermal shock at different temperatures and multiple thermal shocks at a certain temperature was studied and the mechanism of performance damage was explored.The results show that under the action time of 1s, Temperature below 610 ℃, single or multiple thermal shock on the mechanical properties of the alloy without obvious damage; temperature higher than 750 ℃; thermal shock significantly affect the mechanical properties of the alloy, strength and elongation with the heat shock times increased significantly decreased. The microscopic analysis shows that the increase of the thermal shock temperature and the number of thermal shocks promote the grain refinement and make the precipitation of the material obviously change.The precipitation of a large amount of flaky η phase at higher than 750 ℃ and The coarsening and uneven distribution of γ-enhanced phase are the main causes of the significant decrease of strength and elongation of J75 stainless steel.