Linear friction welding is a solid-state joining technology that bonds materials via friction heating and plastic deformation. This process is being extensively researched for welding metallic sheets with different dimensions; however, it involves difficulties in joining thin cross-sections due to extensive misalignment and unsteady plastic extrusion of softened materials at interfaces. This study introduces novel efforts for joining thin cross-sections through pressure-controlled oscillations and displacements, facilitating localized plastic flow essential for high-strength solid-state bond formation. This method is rare, and the results reveal base metal fractures in tensile-tested welded joints of 2 mm thick S45C steel sheets. The interfacial yielding at specific temperatures is obtained by applying pressure corresponding to the temperature-dependent strength of the material. Accordingly, the welding is attempted using a hydraulic-based clamping system designed to accommodate large sheet lengths while allowing precise control of the interface pressure and temperature to facilitate controlled material plastic discharge. However, the requisite joint evolution tracking remains infeasible due to the intricate weld designs and is instead uncovered through novel numerical investigations. Modeling simultaneous oscillations and forging displacement while maintaining pressure depicted the kinetics of continual interfacial deformation. The transient fluctuations in plastic stress and temperature increments distinguish the stages of forging under different conditions. The computed temperature vs. plastic strain and the measured change in interfacial microstructures from martensite to dynamically recrystallized very fine ferrite with fragmented small cementite explain the lower temperature welding for an increase in applied pressure, enhancing the understanding of linear friction welding of thin steel sections for industrial applications.

中文翻译：

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了解薄钢板压力控制线性摩擦焊接的热机械变化和由此产生的接头完整性


线性摩擦焊接是一种固态连接技术，通过摩擦加热和塑性变形粘合材料。该工艺正在被广泛研究用于焊接不同尺寸的金属板;然而，由于软化材料在界面处的广泛错位和不稳定的塑料挤出，它涉及连接薄截面的困难。本研究介绍了通过压力控制振荡和位移连接薄截面的新方法，促进了对高强度固态键形成至关重要的局部塑性流动。这种方法很少见，结果显示 2 mm 厚的 S45C 钢板的拉伸测试焊接接头中存在贱金属断裂。在特定温度下的界面屈服是通过施加与材料的温度相关强度相对应的压力获得的。因此，尝试使用基于液压的夹紧系统进行焊接，该系统旨在容纳大长度的板材，同时允许精确控制界面压力和温度，以促进受控的材料塑料排放。然而，由于复杂的焊缝设计，必要的联合演化跟踪仍然不可行，而是通过新颖的数值研究来揭示。在保持压力的同时对同步振荡和锻造位移进行建模，描绘了连续界面变形的动力学。塑性应力和温度增量的瞬态波动区分了不同条件下的锻造阶段。计算出的温度与 塑性应变和测量的界面微观结构从马氏体到动态再结晶的非常细的铁素体和碎裂的小渗碳体的变化解释了低温焊接导致施加压力增加，增强了对工业应用中薄钢截面线性摩擦焊接的理解。