小孔钨极惰性气体保护焊K-TIG(Keyhole Tungsten Inert Gas Welding)的强烈氩弧光会对熔池液面与焊件的成像造成干扰。针对其熔池图像呈现边界模糊、特征尺寸差异大、形态不规则的特点,设计了一种基于注意力机制的多尺度特征融合语义分...小孔钨极惰性气体保护焊K-TIG(Keyhole Tungsten Inert Gas Welding)的强烈氩弧光会对熔池液面与焊件的成像造成干扰。针对其熔池图像呈现边界模糊、特征尺寸差异大、形态不规则的特点,设计了一种基于注意力机制的多尺度特征融合语义分割模型,对焊接熔池区域图像进行分割。首先,利用并行结构的多尺度非对称瓶颈单元替换UNet在特征提取过程中的卷积块,加强对不同尺度特征提取的能力,强化对熔池轮廓的表征能力;然后,在上采样阶段使用跨层的注意力模块引导网络模型更加关注熔池的锁孔区域;最后,在进行网络训练之前,对训练集的图片采用Multi-Scale Retinex算法执行颜色和形态的图像增强。实验结果显示,该神经网络的分割结果与熔池实际区域在Dice系数、MIOU以及F1系数的指标上分别达到95.78%、83.32%和91.86%。展开更多
The 12 mm-thick Ti−6Al−4V(TC4)titanium alloy plates were welded using keyhole tungsten inert gas(K-TIG)welding at various heat inputs.The microstructure,grain boundary(GB)characteristics and mechanical properties of t...The 12 mm-thick Ti−6Al−4V(TC4)titanium alloy plates were welded using keyhole tungsten inert gas(K-TIG)welding at various heat inputs.The microstructure,grain boundary(GB)characteristics and mechanical properties of the weld metal zone(WMZ)were analyzed.The test results show that the K-TIG welds are well formed,and no obvious defects are observed when the heat input is 2.30−2.62 kJ/mm.When the heat input gradually increases,αlaths increase in length,andα′phase and residualβphase are reduced.The electron backscatter diffraction(EBSD)test results indicate that the high-angle GB proportion in the WMZ increases with the increase of heat input.The tensile strength of the WMZ gradually decreases and the elongation of the WMZ increases when the heat input increases from 2.30 to 2.62 kJ/mm.The impact toughness of the WMZ increases as the heat input increases.展开更多
基金The authors are grateful for the financial supports from the Key Research and Development Program of Guangdong Province,China(2020B090928003)the Natural Science Foundation of Guangdong Province,China(2020A1515011050)+1 种基金the Science and Technology Base and Talent Special Project of Guangxi Province,China(AD19245150)Guangxi University of Science and Technology Doctoral Fund,China(19Z27).
文摘The 12 mm-thick Ti−6Al−4V(TC4)titanium alloy plates were welded using keyhole tungsten inert gas(K-TIG)welding at various heat inputs.The microstructure,grain boundary(GB)characteristics and mechanical properties of the weld metal zone(WMZ)were analyzed.The test results show that the K-TIG welds are well formed,and no obvious defects are observed when the heat input is 2.30−2.62 kJ/mm.When the heat input gradually increases,αlaths increase in length,andα′phase and residualβphase are reduced.The electron backscatter diffraction(EBSD)test results indicate that the high-angle GB proportion in the WMZ increases with the increase of heat input.The tensile strength of the WMZ gradually decreases and the elongation of the WMZ increases when the heat input increases from 2.30 to 2.62 kJ/mm.The impact toughness of the WMZ increases as the heat input increases.
