Mechanical Properties of Fusion Reactor First Wall Candidate Material JLF1

采用小尺寸试样（1.5 mm CVN, 1 /3 CVN， ssj -拉伸，w -拉伸）广泛研究了JLF1低活化铁素体/马氏体钢（Fe-9Cr-2W-0.2V-Ta）在重中子辐照后的力学性能变化。辐照铁素体/马氏体钢的一个重要问题是其韧脆转变温度的升高。估计中子辐照6Odpa后JLF1的DBTT增加仍低于室温，辐照约25dpa时测得最高DBTT为255K。在DBTT中没有明显的标本大小依赖性。使用SSJ和/或W试样进行拉伸试验的结果表明，JLF1的0.2%抗应力在辐照至15-20dpa时一度升高，随后随着辐照的进一步降低。结果表明，在15 ~ 20dpa时，出现0.2%的抗胁迫最大值，DBTT的剂量依赖性与0.2%抗胁迫的剂量依赖性密切相关。这意味着JLF1中DBTT的变化主要是由辐照引起的硬化机制引起的。

Mechanical property changes of JLF1 low activation ferritic/martensitic steel (Fe-9Cr-2W-0.2V-Ta) after heavy neutron irradiation were widely investigated using small size specimens (l.5 mm CVN, l/3 CVN, SSJ-tensile, W-tensile). One of the most important problems in irradiated ferritic/martensitic steel is increase of the ductile-to-brittle transition temperature (DBTT). DBTT increase in JLF1 after neutron irradiation up to 6Odpa was estimated to be still below room temperature, and the highest DBTT was measured to be 255K following irradiation of about 25dpa. There was no clear specimen size dependence in DBTT.Results of tensile tests using SSJ and/or W specimens showed that 0.2% proof stress of JLF1 once increased with irradiation up to 15-20dpa followed by the decrease with further irradiation. This results indicated that there was a maximum of 0.2% proof stress around 15-20dpa, and that dose dependence of DBTT was closely related to that of 0.2% proof stress. This means that the change of DBTT in JLF1 is considered to be mainly caused by hardening mechanism due to irradiation.