本文關鍵詞：Nb-Mo-Ti-Ni鑄態(tài)合金組織及氫傳輸性能　出處：《哈爾濱工業(yè)大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： Nb-Mo-Ti-Ni合金 鑄態(tài)組織 氫傳輸性能 氫脆

【摘要】：本文主要研究Mo的加入對Nb-Ti-Ni系合金鑄態(tài)組織和氫傳輸性能的影響。采用真空非自耗電弧熔煉制備了四組合金:a組:亞共晶Nb15-xMoxTi42.5Ni42.5(x=0,5,10)、b組:近共晶Nb20-xMoxTi40Ni40(x=0,5,10)、c組:過共晶Nb30-xMoxTi35Ni35(x=0,5,10)、d組:過共晶Nb40-xMoxTi30Ni30(x=0,5,10)。利用掃描電子顯微鏡和X射線衍射分析儀對四組合金的相和微觀組織進行了分析,獲得了Mo的加入對合金凝固路徑的影響規(guī)律。根據微觀組織演化規(guī)律,選取d組合金進行氫溶解、擴散和滲透等傳輸性能測試,建立了Nb-Mo-Ti-Ni合金成分、組織和氫傳輸性能之間的關系。XRD、SEM等結果表明,Mo的加入會導致合金凝固相組成向富Nb區(qū)域靠近。隨著Mo含量逐漸增加,a組和b組合金相組成由初生TiNi加二元共晶[bccNb+TiNi]變?yōu)槌跎鷅cc-Nb加TiNi,在Nb15Mo5Ti40Ni40合金中出現了三元共晶相{[bcc-Nb+TiNi]+Ti2Ni},在Nb5Mo10Ti42.5Ni42.5合金和Nb10Mo10Ti40Ni40合金中出現了Ti2Ni相;c組和d組合金在Mo含量為5%時保持了初生bcc-Nb加二元共晶相[bcc-Nb+TiNi]的相組成,滿足“多相構成、功能分擔”的氫分離合金設計原則,Mo含量為10%時,出現了少量三元共晶相。選擇滲氫性能最好的d組合金進行吸氫和滲氫測試,結果表明,隨著Mo的加入,合金的氫溶解性能明顯下降,氫擴散性能和氫滲透性能先上升,后下降。其中,Nb35Mo5Ti30Ni30合金具有最高的氫滲透性能,在673K下達到3.15×10-8 molH2·m-1·s-1·Pa-0.5,約為純Pd同條件下的1.98倍。通過恒壓緩冷測試表明,Nb30Mo10Ti30Ni30合金抗氫脆性能最好,Mo的加入可以提高合金的抗氫脆性能。氫在合金中的滲透主要遵循溶解-擴散方式,該行為主要發(fā)生在初生bcc-Nb內,Mo的加入會減小bcc-Nb晶格間隙尺寸,降低氫溶解度,提高抗氫脆性能,同時減小了氫跳躍間隙距離導致合金的滲透和擴散性能出現增加,但隨著Mo含量的進一步增加,合金中的低能間隙過多,高能間隙的減少導致氫原子在膜內擴散速度大幅降低。另外,Nb30Mo10Ti30Ni30合金上下游間氫濃度梯度較低,氫原子擴散動力不足也是導致其氫擴散性能和滲透性能發(fā)生下降的原因。
[Abstract]:In this paper, the effect of Mo addition on the as-cast microstructure and hydrogen transport properties of Nb-Ti-Ni alloys was studied. Four groups of alloys were prepared by vacuum non-consumable arc melting. Hypoeutectic Nb15-xMoxTi42.5Ni42.5(. X0. (5) Nb20-xMoxTi40Ni40Ni40Ni40Ni40Ni40Ni40Ni40Ni40Ni40Nb20-xMoxTi40Ni40Ni40Ni40Nb30-xMoxTi35Ni35Ni35Ni35Ni35Nb30-xMoxTi35Ni35Ni35Nb30-xMoxTi35Ni35Ni35 and subeutectic Nb30-@@. Hb40-xMoxTi30Ni30Ni30Nb40-xTi30Ni30Ni30Nb40-xTi30Ni30Ni30Nb40-xTi30Ni30Ni30Nb40-xTi30Ni@@. The phase and microstructure of four groups of alloys were analyzed by scanning electron microscope (SEM) and X-ray diffraction analyzer (XRD). The effect of Mo addition on the solidification path of the alloy was obtained. According to the law of microstructure evolution d group of alloys were selected to test the hydrogen solubility diffusion and permeability. The relationship between the composition, microstructure and hydrogen transport properties of Nb-Mo-Ti-Ni alloy was established. With the addition of Mo, the solidification phase composition of the alloy will be closer to the NB rich region. With the increase of Mo content, the composition of a group and a combination of b are composed of primary TiNi and binary eutectic. [BccNb TiNi was transformed into primary bcc-Nb and TiNi. ternary eutectic phase {in Nb15Mo5Ti40Ni40 alloy was found. [Bcc-Nb TiNi] Ti2Ni}. Ti2Ni phase appeared in Nb5Mo10Ti42.5Ni42.5 alloy and Nb10Mo10Ti40Ni40 alloy. C and d alloys kept primary bcc-Nb and binary eutectic phase when Mo content was 5. [The phase composition of bcc-Nb TiNi meets the requirement of "multiphase composition, function sharing". The design principle of hydrogen separation alloy is that the Mo content is 10%. A small amount of ternary eutectic phase appeared. The hydrogen absorption and hydrogen permeation test of group d alloy with the best hydrogen permeation performance was carried out. The results showed that the hydrogen solubility of the alloy decreased obviously with the addition of Mo. The hydrogen diffusivity and hydrogen permeability increased firstly and then decreased, among which Nb35Mo5Ti30Ni30 alloy had the highest hydrogen permeability. At 673K, 3.15 脳 10 ~ (-8) molH2 路m ~ (-1) 路s ~ (-1) 路s ~ (-1) 路Pa-0.5, about 1.98 times of pure PD. The hydrogen embrittlement resistance of Nb30Mo10Ti30Ni30 alloy is the best. The hydrogen embrittlement resistance of Nb30Mo10Ti30Ni30 alloy can be improved with the addition of Mo. Hydrogen permeation in the alloy mainly follows the dissolution-diffusion mode. The behavior mainly occurs in the addition of Mo in the primary bcc-Nb, which reduces the lattice gap size of bcc-Nb, reduces the hydrogen solubility and improves the hydrogen embrittlement resistance. At the same time, the hydrogen jump gap distance is reduced, the permeability and diffusion properties of the alloy increase, but with the further increase of Mo content, the low energy gap in the alloy is excessive. The decrease of high energy gap leads to a significant decrease in the diffusion rate of hydrogen atoms in the film. In addition, the hydrogen concentration gradient between upstream and downstream of Nb30Mo10Ti30Ni30 alloy is lower than that of Nb30Mo10Ti30Ni30 alloy. The lack of hydrogen diffusion power also leads to the decrease of hydrogen diffusion and permeability.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TG146.416
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本文編號：1429396