基本信息
项目批准号：51705443
申请代码：E0508
项目名称：搅拌摩擦焊周期性响应行为的热力耦合机理研究
项目负责人：钱锦文
依托单位：湘潭大学
研究期限：2018-01-01 至 2020-12-31
资助经费：24.0（万元）
项目摘要
 
中文摘要：
周期性响应行为是搅拌摩擦焊(FSW)与其它摩擦焊方法相比所独有的个性基本特征，其形成原因是恒速（前进速度）驱动摩擦大变形体系导致，目前却将此行为归结为粘塑性金属随搅拌针周期性运动的结果，严重阻碍了对搅拌摩擦焊形成机理的深入认识。本研究提出动力学与热力学相结合的方法，分析FSW周期性响应行为的热力耦合机理问题。首先，基于同质和异质摩擦实验，建立摩擦大变形体系的热力耦合表征。其次，通过物理模拟恒速驱动摩擦大变形体系的方法，获取材料在恒速驱动下力学响应行为及组织特点的变化规律，分析FSW周期性响应行为的形成机理。通过借鉴PLC效应研究方法和非线性动力学，建立搅拌针前沿粘塑性金属的失稳判据。最后，在上述研究基础上，分别从动力学与非平衡热力学出发，研究FSW周期性响应行为与其摩擦大变形体系形成与演变的时、空统一性问题。研究成果将为搅拌摩擦焊制造供工艺理论基础，并为接头可靠性研究提供理论支撑。
英文摘要：
The periodic response behavior of friction stir welding (FSW) is the unique personality characteristics compared with other friction welding method, which causes by the constant speed (travel speed) driving severe plastic deformation system. However, the opinion that this periodic response behavior is the visco-plastic metal moving with the periodic movement of the stir pin, not only is indiscreet but also impedes further understanding the nature of plastic flow and mechanism of weld forming mechanism of friction stir welding. This proposal suggests the method of combining dynamics and thermodynamics to analyze the intrinsic thermal mechanical coupling mechanism of FSW periodic response behavior. Firstly, based on the homogeneous and heterogeneous friction experiments, the thermal mechanical coupling characteristics of the severe plastic deformation system are established. Secondly, according to physical simulation of constant speed driven severe plastic deformation system of FSW, the response behavior and microstructure characteristics of the speed driven deformation material is obtained, and the formation mechanism of the periodic response behavior during FSW processing. Based on the PLC effect method and the nonlinear mechanics, the unstability criterion of the viscoplastic metal in the front of the stir pin is established. Finally, based on the basis of dynamics and non-equilibrium thermodynamics, the analytical model of the temporal and spatial distribution of the severe plastic deformation system and the periodic response behavior produced by FSW is proposed. The research will enrich the fundamentals of process theory on friction stir welding and support the further study on joint reliability.
 
                                                                                                                                                                                                        ——来自https://kd.nsfc.gov.cn/