本文選題：鎢合金 + 塑性加工��； 參考：《北京科技大學》2016年博士論文

【摘要】：核聚變能是解決未來人類能源需求的重要途徑。制約核聚變應用的關鍵問題之一是面向等離子體材料(PFMs)的發(fā)展。PFMs在服役過程中會受到輻照和熱流沖擊。鎢(W)材料以其高熔點,高熱導率,優(yōu)異的高溫力學性能和低氘／氚滯留等特點被認為是PFMs的最主要候選材料。但是,鎢材料的嚴重脆性限制了其在核聚變堆中的真正應用�，F已證明塑性變形和第二相摻雜可以改善鎢材料的脆性。另外,抗瞬態(tài)熱流載荷性能和抗粒子輻照性能也決定著PFM能否滿足核聚變裝置應用要求。因為鎢晶粒的抗粒子輻照性能與其晶體取向有關,所以通過調節(jié)鎢材料的織構特點可以改善其抗粒子輻照性能。因此本文通過塑性變形工藝制備了純鎢(PW),氧化鑭彌散鎢(W-1.0wt%La2O3,簡稱WL10)和鉀泡彌散鎢(W-K),研究其微觀組織、織構化程度、力學性能尤其是強度、韌脆轉變溫度(Ductile-Brittle Transition Temperature,簡稱DBTT)和熱導率等指標,并評價其抗瞬態(tài)熱流載荷性能和織構特點。首先,通過單向軋制工藝制備了不同變形量的純鎢、鑭鎢材料。對于純鎢材料而言,與其他軋制變形量相比較,60%軋制變形量樣品具有最高的抗彎強度(1068 MPa)、最低的DBTT(823-873 K)、最高的熱導率(176.5 W/mK)和最高的夏比沖擊功。對于鑭鎢而言,與其他軋制變形量相比較,52%軋制變形量樣品具有較高的抗彎強度(1312 MPa)、最低的DBTT(723-773 K)、較高的熱導率(140.1 W/mK)和最高的夏比沖擊功。所以純鎢、鑭鎢材料的最優(yōu)軋制變形量分別為60%和52%。中間變形量樣品不僅具有晶粒細化效應、亞結構韌化效應而且避免了由織構化程度高和顯微裂紋誘發(fā)的脆斷。此外,我們選擇“旋鍛+軋制”新工藝制備了鉀鎢材料,并將其與60%軋制變形量純鎢、52%軋制變形量鑭鎢作比較。結果表明纖維化程度(纖維結構的長徑比)、織構化程度(主要織構的體積占有率)、顯微裂紋、動態(tài)再結晶和第二相是影響鎢基材料強韌性的主要因素�！靶�+軋制”鉀鎢具有最低的抗彎強度(856MPa)和最高的DBTT(923 K),這主要是由其樣品中存在的顯微裂紋導致的。52%軋制變形量鑭鎢具有最高的強度(1312 MPa)、最低的DBTT(723-773)和最高的夏比沖擊功,這主要是由于其樣品中顯微裂紋較少,同時具有較多的動態(tài)再結晶晶粒以及La203顆粒對位錯和晶界的釘扎作用。相比之下,60%軋制變形量純鎢具有居中的強度(1068 MPa)和DBTT(823-873 K)。另外,與60%軋制變形量純鎢相比較,“旋鍛+軋制”鉀鎢的夏比沖擊功更高,這是因為鉀鎢樣品中存在鉀泡對位錯的釘扎效應和可能的湮滅效應。然后,通過EMS-60裝置對60%軋制變形量純鎢,52%軋制變形量鑭鎢、“旋鍛+軋制”鉀鎢的抗瞬態(tài)電子束熱沖擊和抗瞬態(tài)電子束熱疲勞性能進行評價。結果表明,對于60%軋制變形量純鎢而言,其裂紋閾值介于0.22-0.44GW/m2之間,熔化閾值和再結晶閾值均高于1.1 GW/m2。對于52%軋制變形量鑭鎢而言,其裂紋閾值低于0.22 GW/m2,熔化閾值介于0.66-0.88 GW/m2之間,再結晶閾值高于1.1 GW/m2。對于“旋鍛+軋制”鉀鎢而言,其裂紋閾值介于0.44-0.66 GW/m2之間,熔化閾值高于1.1 GW/m2,再結晶閾值介于0.44-0.66 GW/m2之間。在抗瞬態(tài)電子束熱疲勞性能方面,60%軋制變形量純鎢經過1000次、0.24 GW/m2熱疲勞后表面出現裂紋,52%軋制變形量鑭鎢經過100次、0.17 GW/m2熱疲勞后表面出現裂紋,“旋鍛+軋制”鉀鎢經過1000次、0.44 GW/m2熱疲勞后表面無裂紋而僅出現表面粗糙化和再結晶現象。鉀泡對位錯的釘扎效應和可能的湮滅效應是“旋鍛+軋制”鉀鎢具有最好的抗瞬態(tài)熱流載荷性能的主要原因�；w的低熱導率和La203顆粒的分解,熔化是52%軋制變形量鑭鎢具有最差的抗瞬態(tài)熱流載荷性能的主要原因。最后,我們第一次系統(tǒng)地研究了軋制方式、軋制變形量、彌散La203和再結晶退火對鎢基材料的織構特點影響。結果表明,1)與交叉軋制和周向軋制純鎢相比較,單向軋制純鎢具有較強的{100}面織構和較弱的{111}面織構。2)熱軋過程中的動態(tài)回復和動態(tài)再結晶是影響鎢基材料織構變化的主要因素。動態(tài)回復導致72%、80%軋制變形量純鎢和43%、57%、72%軋制變形量鑭鎢的{001}110織構增強；動態(tài)再結晶導致80%軋制變形量純鎢和72%軋制變形量鑭鎢的{001}100織構增強。3)再結晶退火導致單向軋制、周向軋制純鎢的{100}面織構體積分數升高并且導致交叉軋制、周向軋制純鎢的{111)面織構體積分數降低。
[Abstract]:Nuclear fusion can be an important way to solve the future human energy demand. One of the key problems that restricts the application of nuclear fusion is the development of plasma material (PFMs) for the development of.PFMs in the course of service, which will be subjected to radiation and heat shock. Tungsten (W) materials are characterized by high melting point, high thermal conductivity, excellent high temperature mechanical properties and low deuterium / tritium retention and so on. It is considered to be the most important candidate for PFMs. However, the serious brittleness of tungsten materials restricts its real application in the nuclear fusion reactor. It has been proved that plastic deformation and second phase doping can improve the brittleness of tungsten materials. In addition, the resistance to transient heat flux and the resistance to particle irradiation also determine whether PFM can meet the application of nuclear fusion devices. Requirements. Because the anti particle irradiation properties of tungsten grains are related to their crystal orientation, so by adjusting the texture characteristics of tungsten materials, the properties of their anti particle irradiation can be improved. So in this paper, pure tungsten (PW), W-1.0wt%La2O3 (WL10) and potassium diffusion tungsten (W-K) are prepared by plastic deformation process, and the microstructure of the tungsten particles is studied. Construction degree, mechanical properties especially strength, toughened and brittle transition temperature (Ductile-Brittle Transition Temperature, DBTT) and thermal conductivity, and evaluation of its transient thermal current load performance and texture characteristics. First, pure tungsten, lanthanum tungsten materials with different deformation quantities were prepared by unidirectional rolling process. For pure tungsten materials, and others Compared with the rolling deformation, the 60% rolling deformation samples have the highest bending strength (1068 MPa), the lowest DBTT (823-873 K), the highest thermal conductivity (176.5 W/mK) and the highest Charpy impact power. For lanthanum tungsten, compared with other rolling deformation, the 52% rolling deformation samples have higher bending strength (1312 MPa) and the lowest DBTT ( 723-773 K), higher thermal conductivity (140.1 W/mK) and the highest Charpy impact power. Therefore, the optimum rolling deformation of pure tungsten and lanthanum tungsten materials is 60% and 52%. intermediate deformation samples not only have grain refinement effect, substructure toughening effect but also avoid the brittle fracture induced by high texturing degree and microcrack. In addition, we choose " The new process of rotary forging + rolling is used to prepare potassium and tungsten materials and compare them with the 60% rolling deformation quantity pure tungsten and 52% rolling deformation amount of lanthanum tungsten. The results show that the degree of fibrosis (the length to diameter ratio of fiber structure), the degree of texturing (the volume occupancy of the main texture), the microcrack, the dynamic recrystallization and the second phase are the main factors affecting the strength and toughness of the tungsten based materials. Factors. "Spin forging + rolling" potassium tungsten has the lowest bending strength (856MPa) and the highest DBTT (923 K), which is mainly caused by the microcracks in the samples of its samples, the.52% rolling deformation of lanthanum tungsten has the highest strength (1312 MPa), the lowest DBTT (723-773) and the highest Charpy impact work, mainly due to the microcracks in the samples. Fewer, more dynamic recrystallized grains and La203 particle pinning effect on dislocation and grain boundary. In comparison, the 60% rolling deformation of pure tungsten has a medium strength (1068 MPa) and DBTT (823-873 K). In addition, the Charpy impact work of "rotary + rolling" of potassium tungsten is higher than that of pure tungsten with 60% rolling deformation, which is due to potassium tungsten. The pinning effect and possible annihilation effect of potassium vesicles on dislocations exist in the samples. Then, the anti transient electron beam thermal shock resistance and transient electron beam thermal fatigue resistance of 60% rolled pure tungsten, 52% rolling deformation amount of lanthanum tungsten, "rotary forging + rolled" potassium tungsten are evaluated by the EMS-60 device. The results show that the 60% rolling deformation is pure tungsten. The threshold of the crack is between 0.22-0.44GW/m2, the melting threshold and the recrystallization threshold are higher than 1.1 GW/m2.. The threshold of the crack is lower than 0.22 GW/m2 for the 52% rolling deformation of lanthanum and tungsten, the melting threshold is between 0.66-0.88 GW/m2 and the recrystallization threshold is higher than 1.1 GW/m2. for "rotary + rolled" potassium tungsten. The crack threshold is between 0.44- and 0.44-. Between 0.66 GW/m2, the melting threshold is higher than 1.1 GW/m2, and the recrystallization threshold is between 0.44-0.66 GW/m2. In the anti transient electron beam thermal fatigue property, the 60% rolling deformation amount of pure tungsten is 1000 times, the surface cracks after 0.24 GW/m2 thermal fatigue, 52% rolling deformation amount of lanthanum tungsten through 100, 0.17 GW/m2 thermal fatigue surface cracks, "spin forging +" The surface roughness and recrystallization of the rolled potassium tungsten after 1000 times and 0.44 GW/m2 thermal fatigue are only surface roughness and recrystallization. The pinning effect and possible annihilation effect of potassium vesicles on dislocation are the main reasons for the best resistance to transient heat flux of "rotary forging + rolling" of potassium tungsten. The low thermal conductivity of matrix and the decomposition of La203 particles are the main reasons. Melting is the main reason for the worst resistance to transient heat flux of the 52% rolling deformation of lanthanum. Finally, we first systematically studied the rolling mode, the rolling deformation, the dispersion La203 and the recrystallization annealing on the texture characteristics of tungsten based materials. The results showed that 1) compared with the cross rolling and the circumferential rolling of pure tungsten, unidirectional rolling. The dynamic recovery and dynamic recrystallization in the hot rolling process of pure tungsten have strong {100} texture and weak {111} texture.2. The dynamic recovery and dynamic recrystallization are the main factors affecting the texture changes of tungsten based materials. The dynamic recovery leads to 72%, 80% rolling deformation of pure tungsten and 43%, 57%, 72% of the {001}110 texture of the tungsten in the rolling deformation of lanthanum; dynamic recrystallization leads to 80% rolling. The {001}100 texture enhanced.3 by the deformation of pure tungsten and 72% rolling deformation of lanthanum tungsten, the recrystallization annealing leads to unidirectional rolling. The volume fraction of the {100} surface texture of the circumferential Rolled Pure Tungsten increases and leads to the cross rolling, and the texture volume fraction of the {111 surface of the circumferential tungsten is reduced.
【學位授予單位】：北京科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TL627;TG339

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