基本信息
项目批准号：51705339
申请代码：E0508
项目名称：回填式搅拌摩擦点焊断裂机制研究
项目负责人：
吕赞
依托单位：
沈阳航空航天大學(xué)
研究期限：2018-01-01 至 2020-12-31
资助经费：25.0（万元）
项目摘要
中文(wén)摘要：
回填式搅拌摩擦点焊（Refil friction stir spot welding，RFSSW）是一种在实际生产中有(yǒu)望取代传统電(diàn)阻点焊和铆接工艺的新(xīn)型焊接技术。國(guó)内外已有(yǒu)研究主要集中在焊接参数对显微组织与力學(xué)性能(néng)的影响，而对于RFSSW接头的断裂机制尚不明确。本课题以2024铝合金為(wèi)研究对象，通过对温度、压力、原子扩散与材料软化等的研究揭示点焊接头的断裂机制。利用(yòng)有(yǒu)限元模拟与试验研究相结合的方法研究不同工艺参数下温度与压力的演变规律；建立基于EAM势函数的分(fēn)子动力學(xué)模型，研究焊接过程的原子扩散行為(wèi)，讨论典型界面固态焊合的机理(lǐ)。利用(yòng)Inverse model方法研究不同显微组织下的力學(xué)性能(néng)，建立一种考虑hook缺陷与微观力學(xué)性能(néng)的RFSSW搭接接头的内聚力断裂裂纹扩展模型，揭示“焊接参数—微观组织—力學(xué)性能(néng)”三者间的相关性，為(wèi)推动RFSSW焊接机理(lǐ)的研究及实际工程的应用(yòng)奠定理(lǐ)论基础。
英文(wén)摘要：
Refill friction stir spot welding(RFSSW) is a novel welding technique which is potential to replace conventional resistance spot welding and riveting process in practical production. The existing research at home and abroad is concentrated on effects of welding process parameters on mechanical properties of RFSSW joint.However, fracture mechanism of RFSSW joint is not clear at present. In this study, chosen 2024 aluminum alloy as research object, the fracture mechanism of RFSSW joint is revealed by analyzing the aspects of temperature, pressure, atom diffusion and softening of materials. Evolution law of temperature and pressure under different process parameters is also investigated by means of the method of combining finite element model(FEM) with experimental research. Meanwhile, in order to study the atom diffusion behavior and discuss the mechanism of solid state bonding of typical interface, molecular dynamic model based on EAM potential function is established. In addition, using Inverse model method to research mechanical property under different microstructures and building cohesive crack propagation model of RFSSW joint considering hook defect and mechanical property are utilized to reveal the correlations of welding parameters, microstructures andmechanical property, which lays the theoretical basics for promoting the research of RFSSW mechanism and application in practical engineering.
——来自https://kd.nsfc.gov.cn/
