發(fā)布時(shí)間：2018-03-28 02:36

  本文選題：多尺度準(zhǔn)連續(xù)介質(zhì)法　切入點(diǎn)：Ⅰ型裂紋　出處：《物理學(xué)報(bào)》2016年19期

【摘要】：采用多尺度準(zhǔn)連續(xù)介質(zhì)法計(jì)算模擬了鉭、鐵、鎢三種體心立方(body-centered-cubic,BCC)金屬的I型裂紋斷裂過程.觀察了加載過程中裂紋尖端區(qū)域原子的位錯(cuò)、孿晶等塑性變形現(xiàn)象,以及裂紋的脆性開裂和擴(kuò)展現(xiàn)象.模擬結(jié)果表明,不同BCC金屬材料的裂紋在相同的加載下有不同韌脆性表現(xiàn).在一定變形范圍內(nèi),鉭裂紋主要表現(xiàn)出的是裂紋尖端附近區(qū)域原子的位錯(cuò)和形變孿晶等塑性變形現(xiàn)象;鐵裂紋在變形過程中先后表現(xiàn)出了塑性變形和脆性擴(kuò)展現(xiàn)象,與實(shí)驗(yàn)結(jié)果吻合;鎢裂紋在變形過程中則主要變現(xiàn)出脆性擴(kuò)展現(xiàn)象.計(jì)算了三種金屬材料的廣義層錯(cuò)能曲線,得到其不穩(wěn)定層錯(cuò)能;并分別用兩種不同的韌脆性準(zhǔn)則,對三種材料斷裂模型的韌脆性行為進(jìn)行分析,計(jì)算分析結(jié)果與模擬結(jié)果一致,從而驗(yàn)證了模擬結(jié)果的正確性.
[Abstract]:The mode I crack fracture process of tantalum, iron and tungsten body-centered-cubic-BCCs has been simulated by means of multi-scale quasi-continuum method. The plastic deformation phenomena of dislocations and twins in the crack tip region have been observed during loading. The simulation results show that different BCC metallic materials exhibit different ductile brittleness under the same loading. Tantalum cracks mainly show plastic deformation phenomena such as dislocations and deformation twins of atoms near the crack tip, and iron cracks exhibit plastic deformation and brittle propagation in the process of deformation, which are consistent with the experimental results. In the process of deformation, the brittle propagation of tungsten cracks is mainly realized. The generalized stacking fault energy curves of three kinds of metallic materials are calculated, and the unstable stacking fault energies are obtained, and two different ductile brittleness criteria are used respectively. The ductile brittleness behavior of three fracture models is analyzed, and the calculated results are in agreement with the simulation results, which verifies the correctness of the simulation results.
【作者單位】： 復(fù)旦大學(xué)航空航天系;
【基金】：國家自然科學(xué)基金(批準(zhǔn)號:11572090)資助的課題~~
【分類號】：O346.1
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本文編號：1674409