金属材料的韧脆转变温度（DBTT）的精确测量对先进核能装置的安全性和寿命评估具有重要意义。但是传统的DBTT测量费时费料，迫切需要发展小试样检测方法或者非破坏性检测方法来测量DBTT，以克服先进核能装置中监测仓内试样数量的限制。本项目针对迄今为止还没有比较成熟和可靠的DBTT无损检测技术的问题，在研制高精度大振幅激发多功能内耗仪的基础上，选择低合金钢和金属钨为模型材料，对基于磁性测量和内耗测量的DBTT无损检测原理和方法进行深入系统的研究，阐明关键参数（如矫顽力和内耗随应变振幅急剧上升的临界应变振幅）随温度的变化规律及其与DBTT相关性的物理本质，建立无损和快速检测材料DBTT的新实验方法和技术。本项目的研究成果将为反应堆结构材料由于中子辐照导致的DBTT改变提供快速有效的监测方法，同时也将为其它材料DBTT的快速测量提供技术手段。

The accurate measurement of ductile brittle transition temperature (DBTT) of mattelic materials is of very importance for the evaluation of safety and lifetime estimation of advanced nuclear power equipments. However, the traditional techniques for DBTT measurement are both time and materials consuming. It is very urgent to develop the small specimen method or nondestructive method for DBTT measurement, in order to break through materials limitation in the surveillance cabins of the advanced nuclear power equipments. Facing the problem that there are not any well-rounded and reliable nondestructive method for DBTT measurement, this project was launched to design and build high accuracy and high strain amplitude activated torsion pendulum, to systematically investigate the principles of the internal friction and magnetic measurement based t nondestructive methods for DBTT measurement by choosing low-alloyed steels and pure tungsten as model materials, to illustrate the physical mechanism for the variation of the key parameters (such as coercive force and critical strain amplitude corresponding to the rapid increase of internal friction with strain amplitude) with temperature and its relevance to DBTT, to build new experimental techniques for nondestructive measurement of DBTT. The results of this project would afford effective method to evaluate the DBTT change of structural materials induced by neutron irradiation nuclear reactors, as well as to afford techniques of rapid measurement of DBTT for other materials.