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）研究了JLF 1低活化铁素体/马氏体钢（Fe-9 Cr-2 W-0. 2 V-Ta）在重中子辐照后的力学性能变化。辐照铁素体/马氏体钢的最重要的问题之一是韧脆转变温度（DBTT）的增加。JLF 1的DBTT增加后，中子照射高达60 dpa的估计仍然低于室温，并测量到最高的DBTT为255 K后，照射约25 dpa。对SSJ和W试样的拉伸试验结果表明，JLF 1的0.2%屈服强度随辐照强度的增加而增加，但在15- 20 dpa范围内，随辐照强度的增加而减小。结果表明，0.2%的弹性极限应力在15- 20 dpa附近有一个最大值，DBTT的剂量依赖性与0.2%的弹性极限应力密切相关。这意味着JLF 1中DBTT的变化被认为主要是由辐照硬化机制引起的。

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.