This study was conducted to investigate the capability of multi-pass friction stir processing (FSP) on microstructure modification and mechanical properties improvement of FVS0812 alloy. FSP was performed at different rotation speeds (1250, 1600, 2000, and 2500 rpm) and traverse speeds (8, 12, and 25 mm/min) for one, two, and four passes. According to the results, applying single-pass FSP at optimized conditions (i.e. 1600 rpm and 12 mm/min) enhanced the tensile strength, fracture strain, and microhardness of the alloy by about 1020, 1050, and 60%, respectively. This improvement can be mainly attributed to the intense breakage and uniform distribution of θ-Al₁₃Fe₄ and α-Al₁₂(Fe,V)₃Si intermetallics within the matrix, formation of ultrafine recrystallized grains, and elimination of casting defects. Increasing the number of FSP passes up to four slightly decreased the average size of intermetallic particles, but significantly improved their distribution within the matrix which led to 18 and 200% improvement of tensile strength and fracture strain of one-pass FSPed sample, respectively. The fractography results also revealed that multi-pass FSP has changed the fracture mode of Al-8.5Fe-1.3V-1.7Si alloy from low-energy brittle to a more ductile-dimple fracture.

中文翻译：

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通过摩擦搅拌工艺提高铸造Al-8.5Fe-1.3V-1.7Si（FVS0812）合金的机械性能

进行这项研究以研究多道次摩擦搅拌处理（FSP）对FVS0812合金的显微组织改性和力学性能改善的能力。FSP以不同的转速（1250、1600、2000和2500 rpm）和横向速度（8、12和25 mm / min）进行一遍，两遍和四遍。根据结果​​，在最佳条件下（即1600 rpm和12 mm / min）应用单程FSP可使合金的拉伸强度，断裂应变和显微硬度分别提高约1020％，1050％和60％。这种改进可主要归因于激烈的破裂和均匀分布θ-Al系₁₃的Fe ₄和的α-Al ₁₂（FE，V）₃基质中的硅金属间化合物，形成超细重结晶晶粒，并消除铸造缺陷。将FSP通过的次数增加至四次，会略微减少金属间颗粒的平均尺寸，但会显着改善其在基体内的分布，从而分别使单次FSPed样品的拉伸强度和断裂应变分别提高18％和200％。断口扫描结果还表明，多道次FSP已将Al-8.5Fe-1.3V-1.7Si合金的断裂模式从低能脆性转变为更具延性凹痕的断裂。