【作者】 丛慧；

【导师】 刘锦云； 谌继明；

【作者基本信息】 西华大学 ， 材料学， 2006， 硕士

【摘要】 作为聚变堆的候选结构材料,钒合金的高温强度,热能应力因子以及中子辐照低活化性能等等,相比铁素体/马氏体钢更优良。现今它正作为一种新型的工程材料而受到人们的普遍关注,尤其是在热核反应堆中的应用。在国外,己被认为是较理想的反应堆内壁材料。钒合金具有高的蠕变强度,可以承受比不锈钢高4～7倍的热负荷。它对环境的损害小,具有长期稳定的低放射性、低的衰变热、低的接触放射剂量,并可回收利用,显示出了良好的安全性以及环境上的优势。此外钒合金与液态金属良好的相溶性,不与碱金属(如锂等)反应,它最有可能应用于液态金属冷却系统巾。钒合金还具有良好的加工性能,它可以被轧成薄片,挤压成管状及进行焊接。 钒合金与间隙杂质H、O、N、C等有相对高的亲合力,这是钒合金应用的一个主要问题,氢脆及氢致硬化仍是氢对钒合金应用的影响的重要问题。为了进一步探索含氢钒合金存工程应用中的力学性能,本论文选用了两种成分的钒合金,一部分进行气相渗氢,另一部分不渗氢,然后对他们进行了力学性能测试及断口形貌分析,研究了氢对钒合金的影响,探讨了无氢及含氢的钒合金分别在不同拉伸速率、不同恒载时间以及在不同外加应力下的拉伸性能,通过对实验前后钒合金中氢含量的测量以及对钒合金拉伸性能参数的分析,研究了试样中氧的变化以及对钒合金力学性能的影响,还观察了渗氢前后断口的微观形貌。更多还原

【Abstract】 Vanadium alloys are better than ferritic/matensitic as attractive candidate materials for neutron interactive structural components of fusion energy system, because of their high temperature strength, high thermal stress factor, low activation for neutron irradiation and so on. Now it would be attention as a new kind of engineering material, especially for using in thermal reactors. Vanadium alloy is considered as one of the perfect wall materials of fusion reactor. Vanadium alloys can withstand higher heat load than stainless steel because of higher creep strength. It has less impact on environment, low radioactivity, low decay heat and low contact radiation dose rate for long time, and it can recycle. These properties offer it good safety and friendly environmental features. Furthermore, vanadium alloys have good compatibility with liquid metal, do not react with alkali metal, so it is likely to be used in cooling system with liquid metal fluid. Vanadium alloys have good machining performance;it can be rolled into sheets, extruded as tube and welded.It is mostly concerned that vanadium alloys have relatively high affinity withinterstitial impurities as H> Ch N% C and so on. Hydrogen-induced hardening and embrittlement are still important issues for the effect of hydrogen on vanadium alloys. For further studying the mechanical property of vanadium alloys with hydrogen used in engineering, this paper chooses two kinds of vanadium alloys. The mechanical properties and SEM observation of the fracture surfaces were investigated, from which the effect of hydrogen on vanadium alloys was analyzed. The tensile behaviors of vanadium alloys with hydrogen and without hydrogen were studied on different tensile rate> different constant loading time and different loading stress, by measuring hydrogen concentration after and before tension and analyzing mechanical properties. The change of hydrogen and mechanical properties were investigated, beside those, the microstructure of fracture surface was observed.The testing results indicate: hydrogen-induced hardening improved strength of vanadium alloys, and decreased toughness, which were also proved by fracture surface features. Hydrogen concentration affected the increment of strength as well. In the engineering application, vanadium alloys operate under loading, so the effect of stress on hydrogen behaviors of vanadium alloys can cause the change of mechanical properties. In the process of tensile, hydrogen released from vanadium alloys, and on the high stress loading, temperature creep can be occurred for vanadium alloys. These phenomena show hydrogen-induced hardening, hydrogen-induced unsteady change of elastic property and strength. These could bring about additional safety issues and should be further studied for a fully understanding of the behavior to avoid such instability.更多还原