异种高熵合金CuCoCrFeNi和AlCoCrFeNi的激光焊接头组织和性能研究

发布时间：2018-04-14 10:23

  本文选题：高熵合金 + 激光焊接　； 参考：《材料科学与工艺》2017年04期

【摘要】：为开展异种高熵合金激光焊接性研究,采用光纤激光对1.2 mm厚的异种高熵合金CuCoCrFeNi和AlCoCrFeNi实施了对接焊试验,利用金相观察、EDS、XRD和显微硬度计等方法对接头组织和性能进行测试.研究表明:在经历焊接热循环后,HAZ的金相组织没有发生明显变化;在FZ附近发现两种不同类型的显微组织(柱状晶和胞状晶),WM中心区由等轴晶组成;WM区内各元素均匀分布,FZ附近区域焊缝晶界处存在Cu、Al元素的偏聚,与母材相比,该偏聚现象明显减弱;焊缝横截面的显微硬度略高于CuCoCrFeNi合金,远低于AlCoCrFeNi合金;异种接头拉伸试样断裂位置发生在AlCoCrFeNi合金母材处,接头的抗拉强度σb为166 MPa,断口形式为解理断裂,其断口形貌为扇形花样与河流状花样(无撕裂棱).与母材组织相比,焊缝区晶粒明显细化,且焊缝仍为高熵合金.
[Abstract]:In order to study the laser weldability of dissimilar high-entropy alloy, the butt welding experiments of 1.2mm thick dissimilar high-entropy alloy CuCoCrFeNi and AlCoCrFeNi were carried out by using optical fiber laser. The microstructure and properties of the joints were tested by metallographic observation, EDS-XRD and microhardness meter.The results show that the microstructure of HAZ does not change obviously after welding heat cycling.In the vicinity of FZ, two different types of microstructures (columnar crystal and cellular crystal) are found in the central region of WW M, which are composed of equiaxed crystals and uniform distribution of each element in the Weld grain boundary near FZ. Compared with the base metal, there exists a segregation of Cu-Al elements at the grain boundary of weld in the vicinity of FZ.The segregation phenomenon is obviously weakened, the microhardness of weld cross section is slightly higher than that of CuCoCrFeNi alloy and far lower than that of AlCoCrFeNi alloy, the fracture position of tensile specimen of dissimilar joint occurs at the base metal of AlCoCrFeNi alloy, the tensile strength 蟽 b of the joint is 166MPa, and the fracture is cleavage fracture.The fracture surface is fan-shaped pattern and fluvial pattern (without tearing edge).Compared with the microstructure of base metal, the grain size in the weld zone is finer, and the weld is still a high entropy alloy.
【作者单位】： 沈阳理工大学材料科学与工程学院;中国科学院沈阳金属研究所;深圳市大族激光科技股份有限公司;
【基金】：国家重点基础研究发展计划(973计划)资助项目(2011CB610405)
【分类号】：TG456.7
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本文编号：1748906