工艺参数对Al_2O_3/TC4合金接头界面组织及力学性能的影响

Effect of processing parameters on microstructure and mechanical properties of Al_2O_3/TC4 alloy joints

采用Cu+B钎料分别在钎焊温度890～970℃,保温时间为10 min;钎焊温度为930℃,保温时间0～30 min条件下,钎焊Al2O3陶瓷与TC4合金.利用SEM,EDS和压剪试验研究接头界面组织及力学性能.结果表明,随钎焊温度升高或保温时间的延长,Ti4(Cu,Al)2O层增厚,紧邻其侧生成连续并增厚的Ti2(Cu,Al),Ti2(Cu,Al)含量增加;Ti+Ti2(Cu,Al)含量增加,尺寸变大,分布范围逐渐变宽并向TC4合金侧迁移,TC4合金侧过共析组织区变宽.钎焊温度低于950℃时,TiB晶须主要分布在Ti2Cu晶界处的AlCu2Ti上;当钎焊温度高于950℃时,AlCu2Ti相逐渐消失,TiB晶须主要分布于Ti2Cu上.当保温时间为10 min,钎焊温度为950℃时,接头最大强度为96 MPa;而当钎焊温度为930℃,保温时间为20 min时,接头最大强度为83 MPa.

Al2O3 and TC4 alloy were brazed with Cu+B brazing filler at 890-970 ℃ for 10 min and at 930 ℃ for 0-30 min,respectively.The microstructure and mechanical properties of the resultant joints were investigated with SEM,EDS and shear testing machine.The results indicated that with the increasing of brazing temperature and holding time,the thickness of Ti4(Cu,Al)2O layer increased,next to which continuous and thick Ti2(Cu,Al) existed,and the amounts of Ti2(Cu,Al) and Ti+Ti2(Cu,Al) increased.The size and distribution range of Ti+Ti2(Cu,Al) also increased,which migrated to the TC4 alloy side.The hypereutectoid regions widened near the TC4 alloy.Below 950 ℃,the TiB whiskers were mainly dispersed on AlCu2Ti in grain boundary of Ti2Cu.While above 950 ℃,the AlCu2Ti gradually disappeared,and TiB whiskers were mainly distributed on Ti2Cu.When the holding time was 10 min and brazing temperature was 950 ℃,the maximal joint shear strength was 96 MPa.While the holding time was 20 min and brazing temperature was 930 ℃,and the maximal joint shear strength was 83 MPa.