Effects of cooling condition on microstructural evolution and mechanical properties of friction stir processed 2A14 aluminum alloy
Effects of cooling condition on microstructural evolution and mechanical properties of friction stir processed 2A14 aluminum alloy
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DOI：
10.1088/2053-1591/ab429d
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发表时间：
2019-11
影响因子：
2.3
通讯作者：
Jian Wang;Yalin Lu;Dongshuai Zhou;Yang Zhang;Z. Bai;Xing-cheng Li
中科院分区：
文献类型：
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作者：
Jian Wang;Yalin Lu;Dongshuai Zhou;Yang Zhang;Z. Bai;Xing-cheng Li
对2A 14铝合金在不同冷却条件下搅拌摩擦加工的组织演变和力学性能进行了详细分析。采用SEM、EBSD和TEM等分析手段研究了复合材料的微观组织特征，并进行了显微硬度和拉伸性能测试。结果表明，在搅拌区（SZ）获得了由细小、等轴、高取向差的晶粒组成的显微组织，平均晶粒尺寸为1.19 ~ 3.1 μm。与空冷FSP相比，快速冷却可显著减小SZ中晶粒尺寸、第二相颗粒尺寸和大角度晶界比例。此外，在FSP过程中，在整个SZ中形成具有随机取向的再结晶晶粒。显微织构分析还表明，剪切织构（{hkl} 110和{111} uvw纤维）占主导地位，C和A1* 组分通过几何动态再结晶机制产生。加速冷却使SZ区的织构强度略有增加，表明可能存在不连续动态再结晶细化晶粒的机制。随着冷却速度的提高，搅拌摩擦加工试样的强度和显微硬度均有所提高，这是由于晶粒细化、位错密度增加以及第二相颗粒细小均匀分布所致。
Detailed analysis on the microstructural evolution and mechanical properties of 2A14 aluminum alloy subjected to friction stir processing (FSP) under different cooling conditions has been conducted. SEM, EBSD and TEM were used to reveal the microstructure characteristic, while the microhardness and tensile tests were also performed. The results showed that microstructures formed by fine, equiaxed and highly misoriented grains with the average grain size in the range of 1.19∼3.1 μm were obtained in the stirred zone (SZ). Compared with FSP under air cooling, rapid cooling can significantly reduce grain size, second phase particles size and fraction of high angle grain boundaries in the SZ. Besides, recrystallized grains with random orientation are formed throughout SZ during FSP. The microtexture analysis also demonstrated the dominance of shear texture ({hkl}〈110〉 and {111}〈uvw〉 fibers), with C and A1* components are produced through the geometrically dynamic recrystallization mechanism. And the texture intensity in SZ of the samples is slightly increased with accelerated cooling method, indicating that another mechanism of grain refinement through discontinuous dynamic recrystallization might be involved. Additionally, the strength and microhardness of friction stir processed samples were improved with increasing the cooling rate due to grain refinement, the increase of dislocation density and fine and uniformly distributed second phase particles.