Nuclear energy is a low-carbon, safe, efficient, and sustainable clean energy. The new generation of nuclear energy systems operate in harsher environments under higher working temperatures and irradiation doses, while traditional nuclear power materials cannot meet the requirements. The development of high-performance nuclear power materials is a key factor for promoting the development of nuclear energy. Oxide dispersion strengthened (ODS) steel contains a high number density of dispersed nano-oxides and defect sinks and exhibits excellent high temperature creep performance and irradiation swelling resistance. Therefore, ODS steel has been considered as one of the most promising candidate materials for fourth-generation nuclear fission reactor cladding tubes and nuclear fusion reactor blankets. The preparation process significantly influences microstructure of ODS steel. This paper reviews the development and perspective of several preparation processes of ODS steel, including the powder metallurgy process, improved powder metallurgy process, liquid metal forming process, hybrid process, and additive forging. This paper also summarizes and analyzes the relationship between microstructures and the preparation process. After comprehensive consideration, the powder metallurgy process is still the best preparation process for ODS steel. Combining the advantages and disadvantages of the above preparation processes, the trend applied additive forging for extreme manufacturing of large ODS steel components is discussed with the goal of providing a reference for the application and development of ODS steel in nuclear energy.

为提高铜基粉末冶金摩擦材料的综合性能指标, 用宽带激光束对其进行了激光表面改性处理。采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)仪对微观组织进行了表征, 并用硬度计、摩擦磨损试验机等仪器对性能进行了测试, 结果表明, 宽带激光表面改性处理后, 铜基粉末冶金层的微观结构和性能发生了明显变化。聚合生长状态的α-Cu产生边缘溶解, 大块聚合态α-Cu细小化。在α-Cu内部形成了大量的纳米晶。激光表面改性处理后Cu基粉末冶金摩擦材料层密度提高了6%, 硬度提高12.7%, 耐磨性能提高45％, 摩擦系数提高1％。

利用DC025扩散冷却板条(SLAB)激光器系统地研究了激光焊接三明治金刚石锯片的焊接缺陷和焊接工艺。结果表明焊接缺陷主要表现为焊缝中大量的气孔和较多的铜，降低了焊缝强度。气孔来源于基体里黏接剂、油污与粉末冶金刀头的共同作用，采用正面熔透1/2，反面完全熔透的焊接方式和提高焊接速度来减少气孔缺陷。铜来源于基体里铜板的熔化，当激光偏向刀头时，铜的含量降低。350 mm三明治锯片合适的焊接参数为激光偏移量0～+0.20 mm，正面焊接线能量为25～40 J/mm，且激光功率低于1000 W；反面焊接线能量为80～150 J/mm，且激光功率高于1500 W；此时焊缝铜的质量分数为0.2%～1.1%，焊接气孔较少，焊缝抗弯强度满足EN13236安全标准。

针对薄壁金刚石钻头的激光焊接应用，采用德国LSM240全自动激光焊接系统进行单面焊接试验，建立了粉末冶金材料激光焊接工艺优化的误差反向传播人工神经网络模型，应用该模型研究了激光焊接工艺参数对气孔率和焊缝强度等焊接质量因素的影响，并对薄壁金刚石钻头激光焊接进行了工艺参数优化处理，获得了无气孔缺陷的优质焊接接头。结果表明，气孔率同激光功率、焊接速度之间具有幂函数关系；焊缝强度同激光功率、焊接速度之间具有高斯函数关系。

利用CO2连续激光对预涂石墨和硅混合粉末的Ti-6Al-4V合金进行了熔敷处理。金相分析发现熔敷层内形成了大量的化合物,X射线衍射分析证实形成的化合物主要为SiC,Ti5Si3和TiC等。电子探针分析表明熔敷层内的初晶化合物主要由SiC和TiC组成,共晶化合物则主要是Ti5Si3。熔敷层与金属基体呈良好的冶金结合,其硬度可达2000 Hv0.1,摩擦系数约为0.3,而基体的硬度约为320 Hv0.1,摩擦系数约0.55。可见熔敷层较基体的硬度大为提高,且其耐磨性能较好。激光工艺参数的改变影响着熔敷层的组织和性能,调整工艺参数可获得无气孔和裂纹的熔敷层。

采用LSM240型全自动CO2激光焊接机焊接粉末材料,研究不同粉末材料产生等离子体所需的临界激光功率.粉末配方为:Fe粉+15%羟基Fe粉,Co粉,Ni粉+15%羟基Ni粉三种试样.研究结果表明,Fe,Co,Ni三种试样在CO2激光作用下产生金属蒸气时的临界激光功率密度IC为ICFe＞ICCo＞ICNi;等离子体得以有效控制的下限临界气流量QS为QFeS＜QCoS＜QNiS.