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分别采用CuTi、CuTi+B和CuTi+TiB2钎料,在钎焊温度为930℃,保温时间为10min条件下,钎焊连接Al2O3和TC4合金。通过扫描电子显微镜、透射电子显微镜和压剪试验等方法,研究了接头中生成的TiB晶须对接头组织结构及力学性能的影响。结果表明:B或TiB2粉的添加均可在钎焊接头中原位自生TiB晶须。当钎料中添加B粉时,接头中原位自生的TiB晶须比添加TiB2时的尺寸小。原位自生的TiB晶须可将Al2O3/TC4合金钎焊接头界面分为5个区域,各区分布满足延性–刚性–延性结构,此结构有助于减小降低接头残余应力,提高接头抗剪强度。采用CuTi+TiB2钎料时,Al2O3/TC4合金钎焊接头的抗剪强度最大为143 MPa,比用CuTi钎料时所获接头强度提高了239%。
The CuTi, CuTi + B and CuTi + TiB2 brazing alloys were respectively brazed with Al2O3 and TC4 alloys at brazing temperature 930 ℃ and holding time 10min. The effects of TiB whiskers generated in the joints on the microstructure and mechanical properties of the joint were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and pressure-shear test. The results show that the addition of B or TiB2 powder can self-generate TiB whiskers in the brazed joints. When B powder is added to the brazing filler metal, in-situ TiB whiskers in the joint are smaller than those when TiB2 is added. In-situ TiB whiskers can be divided into five regions of the interface of Al2O3 / TC4 alloy brazing joints, the distribution of the region to meet the ductility - rigid - ductile structure, this structure helps reduce the residual stress joints and improve joint shear strength . When using CuTi + TiB2 brazing filler metal, the maximum shear strength of Al2O3 / TC4 alloy brazed joint is 143 MPa, which is 239% higher than that of CuTi brazing filler metal.