A new technology for the crystallization of ammonium paratungstate with coarse grain has beenstudied. The factors influencing the physi-chemical properties of ammonium paratungstate crystal, such astemperature, concen...A new technology for the crystallization of ammonium paratungstate with coarse grain has beenstudied. The factors influencing the physi-chemical properties of ammonium paratungstate crystal, such astemperature, concentration, seed crystal, agitation. etc. were examined. It is necessary to keep high temperature and low concentration in the process. and the addition of seed crystal and agitation with air is also in favor of the system. Ammonium paratungstate crystal with particle size of 36-42 μm and apparent density of2. 0-2. 2 g·cm- 3 were obtained by controlling suitable technological parameters.展开更多
燃气轮机涡轮叶片在高温、腐蚀以及复杂应力环境下,叶顶容易磨损甚至断裂,通常采用修复的方式降低叶片维护成本,但传统焊接修复具有热影响区大、焊后组织退化的问题,降低了修复叶片的服役寿命。采用激光粉末床熔融(Laser Powder Bed Fus...燃气轮机涡轮叶片在高温、腐蚀以及复杂应力环境下,叶顶容易磨损甚至断裂,通常采用修复的方式降低叶片维护成本,但传统焊接修复具有热影响区大、焊后组织退化的问题,降低了修复叶片的服役寿命。采用激光粉末床熔融(Laser Powder Bed Fusion,L-PBF)修复CM247LC柱状晶叶片,具有热影响区小、可实现柱状晶组织接续的优势。采用不同晶体取向的柱状晶基板模拟受损柱状晶叶片,研究基板晶粒形貌(柱状晶与等轴晶)和取向(基板〈001〉取向//成形方向(Building Direction,BD)、〈111〉//BD、〈110〉//BD)对修复区晶粒外延生长的影响规律。结果表明,采用〈001〉//BD柱状晶基板与等轴晶基板的修复区中〈001〉取向晶粒的含量分别为94.2%和11.1%,柱状晶基板较等轴晶基板更利于柱状晶的外延生长;不同晶粒取向的基板对修复区〈001〉织构含量影响显著,修复区〈001〉织构含量从高到低依次为:〈001〉//BD柱状晶基板,为94.2%;〈111〉//BD柱状晶基板,为34.0%;〈110〉//BD柱状晶基板,为24.4%。展开更多
文摘A new technology for the crystallization of ammonium paratungstate with coarse grain has beenstudied. The factors influencing the physi-chemical properties of ammonium paratungstate crystal, such astemperature, concentration, seed crystal, agitation. etc. were examined. It is necessary to keep high temperature and low concentration in the process. and the addition of seed crystal and agitation with air is also in favor of the system. Ammonium paratungstate crystal with particle size of 36-42 μm and apparent density of2. 0-2. 2 g·cm- 3 were obtained by controlling suitable technological parameters.
文摘燃气轮机涡轮叶片在高温、腐蚀以及复杂应力环境下,叶顶容易磨损甚至断裂,通常采用修复的方式降低叶片维护成本,但传统焊接修复具有热影响区大、焊后组织退化的问题,降低了修复叶片的服役寿命。采用激光粉末床熔融(Laser Powder Bed Fusion,L-PBF)修复CM247LC柱状晶叶片,具有热影响区小、可实现柱状晶组织接续的优势。采用不同晶体取向的柱状晶基板模拟受损柱状晶叶片,研究基板晶粒形貌(柱状晶与等轴晶)和取向(基板〈001〉取向//成形方向(Building Direction,BD)、〈111〉//BD、〈110〉//BD)对修复区晶粒外延生长的影响规律。结果表明,采用〈001〉//BD柱状晶基板与等轴晶基板的修复区中〈001〉取向晶粒的含量分别为94.2%和11.1%,柱状晶基板较等轴晶基板更利于柱状晶的外延生长;不同晶粒取向的基板对修复区〈001〉织构含量影响显著,修复区〈001〉织构含量从高到低依次为:〈001〉//BD柱状晶基板,为94.2%;〈111〉//BD柱状晶基板,为34.0%;〈110〉//BD柱状晶基板,为24.4%。
