本文關(guān)鍵詞：α-Fe晶界的力學(xué)行為及缺陷效應(yīng)　出處：《上海工程技術(shù)大學(xué)》2016年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 分子動(dòng)力學(xué) α-Fe傾側(cè)晶界 He-V團(tuán)簇 納米空洞 位錯(cuò)增殖

【摘要】：α-Fe以其優(yōu)異的抗輻照腫脹和抗腐蝕性能被認(rèn)為是聚變堆第一壁結(jié)構(gòu)材料最具吸引力的候選之一。作為反應(yīng)堆器壁材料,核聚變反應(yīng)中產(chǎn)生的嬗變產(chǎn)物氦進(jìn)入材料內(nèi)部,與材料中的晶界、空洞等缺陷相互作用導(dǎo)致材料微觀結(jié)構(gòu)發(fā)生變化,引起輻照硬化、韌脆轉(zhuǎn)變溫度升高和體積膨脹等問(wèn)題,直接影響聚變堆運(yùn)行的可靠性,給核反應(yīng)堆的安全性提出了嚴(yán)峻的挑戰(zhàn)。本課題借助分子動(dòng)力學(xué)方法對(duì)α-Fe不同傾側(cè)晶界在不同溫度、空洞位置、He原子分布濃度等條件下進(jìn)行模擬分析,研究α-Fe不同傾側(cè)晶界的力學(xué)行為,分析納米空洞、He原子等缺陷對(duì)晶界力學(xué)行為產(chǎn)生的影響。首先分析了α-Fe不同傾側(cè)晶界的力學(xué)性能,發(fā)現(xiàn)晶界的斷裂應(yīng)力、斷裂應(yīng)變和彈性模量與取向角度有關(guān);隨溫度升高,晶界的斷裂應(yīng)變和彈性模量逐漸降低。其次模擬了含缺陷時(shí)晶界的拉伸加載過(guò)程,分析He原子缺陷對(duì)晶界力學(xué)行為的影響,對(duì)比不同He原子分布濃度、溫度、空洞位置條件下原子演變過(guò)程。結(jié)果發(fā)現(xiàn):He團(tuán)簇隨應(yīng)變?cè)黾訑D出附近晶格上的Fe原子形成氦-空位團(tuán),并相互擴(kuò)散連接形成微裂紋導(dǎo)致晶界斷裂;隨He原子分布濃度增加其晶界斷裂由塑性斷裂轉(zhuǎn)變?yōu)榇嘈詳嗔?空洞位置對(duì)晶界中He原子演變過(guò)程有很大影響。最后分析α-Fe含空洞缺陷的∑5{310}100晶界模型在拉伸加載過(guò)程中位錯(cuò)的萌生增殖機(jī)理,結(jié)果表明:空洞遠(yuǎn)離晶界時(shí),空洞周?chē)孛芘琶嫦?個(gè)方向發(fā)射1/2111位錯(cuò)環(huán);空洞位于晶界附近時(shí),空洞遠(yuǎn)離晶界一側(cè)發(fā)射1/2111位錯(cuò)環(huán),而空洞靠近晶界一側(cè)位錯(cuò)環(huán)的發(fā)射受到晶界抑制。
[Abstract]:The excellent anti radiation swelling and corrosion resistance of alpha -Fe is considered to be one of the most attractive candidates for the first wall structure material of the fusion reactor. As the reactor wall material, nuclear fusion reaction in the evolution of helium into the product inside the material, grain boundaries, and material holes in interaction leads to the microstructure of the material changes caused by irradiation hardening, ductile brittle transition temperature and volume expansion and other issues, directly affects the reliability of fusion reactor, put forward a severe challenge to the safety of nuclear reactors. This subject by means of molecular dynamics method of alpha -Fe different tilt grain boundaries in different temperature and hole position, He atom concentration distribution under the simulation analysis, the mechanical behavior of a -Fe different tilt grain boundaries, analysis of the impact of nano void and He atom defects on grain boundaries of mechanical behavior. First analysis of the mechanical properties of -Fe with different tilt grain boundaries, the grain boundary fracture stress, fracture strain and elastic modulus and orientation angle; with the increase of temperature, the fracture strain and elastic modulus of the grain boundary decreases gradually. Secondly, the tensile loading process of grain boundary is simulated, and the effect of He atom defect on the mechanical behavior of grain boundary is analyzed. The evolution process of atoms under different He concentration, temperature and void location is compared. The results showed that He clusters near the Fe atoms on the lattice extrusion forming helium vacancy clusters with increasing strain, and mutual diffusion bonding formation of microcracks leads to intergranular fracture; with the He atom concentration distribution increases the grain boundary fracture changed from ductile fracture to brittle fracture; has a great influence on the evolution of the void position in the process of He atoms at grain boundaries. The final analysis of the initiation mechanism of proliferation, sigma alpha -Fe 5{310}100 grain boundary model containing voids dislocation in tensile loading process in the cavity from grain boundary, near the hole along the close packed face 4 direction emission 1/2111 ring dislocation; voids at the grain boundaries, away from the hole side emitting 1/2111 grain boundary dislocation loops, and the hole near the grain boundary one side of the emission by inhibiting grain boundary dislocation loop.
【學(xué)位授予單位】：上海工程技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：O614.811

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本文編號(hào)：1343509