Ultrafine oxide dispersion strengthening(ODS)-Mo and ODS-W alloy powders containing different types of oxide nanoparticles were successfully synthesized by spraying method(solid−liquid mixing method)combined with the ...Ultrafine oxide dispersion strengthening(ODS)-Mo and ODS-W alloy powders containing different types of oxide nanoparticles were successfully synthesized by spraying method(solid−liquid mixing method)combined with the reductions with carbon black and hydrogen in sequence.It is concluded that the solution concentration and type of rare earth oxide have no effect on the grain size of ODS-Mo alloy powder,but have obvious effect on that of ODS-W alloy powder.The higher the concentration of rare earth solution is,the smaller the average grain size of ODS-W alloy powder is.Furthermore,compared with doping with CeO_(2),the grain sizes of reduction products of La_(2)O_(3) and Y_(2)O_(3) doped WO_(3) are relatively larger.Compared with the undoped case,there is almost no change for grain size of ODS-Mo alloy powder,while the grain size of ODS-W alloy powder becomes much larger.This is probably due to the appearance of the composite oxide(such as La_(2)WO_(6))formed by the reaction between tungsten oxide and rare earth oxides,which promotes the heterogeneous nucleation and growth of tungsten grains during the reduction process of ODS-W,while there is no complex oxide composed of molybdenum and rare earth oxides in the reduction process of ODS-Mo.展开更多
基金financial support from the National Natural Science Foundation of China (No.51734002)。
文摘Ultrafine oxide dispersion strengthening(ODS)-Mo and ODS-W alloy powders containing different types of oxide nanoparticles were successfully synthesized by spraying method(solid−liquid mixing method)combined with the reductions with carbon black and hydrogen in sequence.It is concluded that the solution concentration and type of rare earth oxide have no effect on the grain size of ODS-Mo alloy powder,but have obvious effect on that of ODS-W alloy powder.The higher the concentration of rare earth solution is,the smaller the average grain size of ODS-W alloy powder is.Furthermore,compared with doping with CeO_(2),the grain sizes of reduction products of La_(2)O_(3) and Y_(2)O_(3) doped WO_(3) are relatively larger.Compared with the undoped case,there is almost no change for grain size of ODS-Mo alloy powder,while the grain size of ODS-W alloy powder becomes much larger.This is probably due to the appearance of the composite oxide(such as La_(2)WO_(6))formed by the reaction between tungsten oxide and rare earth oxides,which promotes the heterogeneous nucleation and growth of tungsten grains during the reduction process of ODS-W,while there is no complex oxide composed of molybdenum and rare earth oxides in the reduction process of ODS-Mo.
文摘为评价氧化物弥散强化合金(oxide dispersion-strengthened alloy,ODS)钢的电阻点焊性能,使用金相显微镜及扫描电镜观察了9Cr YWT-ODS钢焊点不同区域的组织,测试了焊点的拉伸剪切性能,确定了合适的焊接电流范围.结果表明,焊点不同区域内氧化相尺寸存在明显差异,热影响区回火区温度较低,氧化相细小,热影响区相变区温度较高,氧化相有所长大,熔核区温度很高,氧化相明显粗化.随着焊接电流增大,熔核尺寸增大导致焊点最大拉伸剪切力升高的同时,失效方式由界面失效逐渐转变为部分界面-部分焊点拔出失效及完全焊点拔出失效,继续增大焊接电流到飞溅产生时,熔核尺寸减小引起最大拉伸剪切力降低,失效方式再次转变为部分界面-部分焊点拔出失效和界面失效.根据拉伸剪切试验结果确定合适的焊接电流范围为6.6~7.0 k A.
