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采用粉末冶金的方法制备了30vol%B_4C/6061Al中子吸收材料板材。通过搅拌摩擦焊(FSW)的方法对4 mm厚30vo1%B_4C/6061A1中子吸收材料板材进行对接焊接,获得了表面成形良好的焊缝。采用纳米压痕法对FSW焊接接头的焊核(WZ)、热力影响区(TMAZ)、热影响区(HAZ)和母材(BM)4个区域中的微区力学性能进行研究,对焊接接头的拉伸性能进行了测试。运用扫描电镜对压痕的微观形貌和拉伸断口进行表征。结果表明:在同一区域中,随着距颗粒/基体界面距离d(d<11μm)的增加,微区的硬度和弹性模量总体呈现降低趋势。在微区数值均值化后,不同区域的硬度和弹性模量由高到低为WZ、TMAZ、BM和HAZ,压入功恢复率在WZ、TMAZ、HAZ和BM依次为28.10%、25.14%、31.76%和29.30%。在焊接接头不同区域出现性能差别的原因是由于在FSW过程中不同区域的塑性变形程度和热循环作用不同导致的,FSW接头强度可达母材的85.7%,断裂部位在HAZ区。
A 30vol% B_4C / 6061Al neutron absorber plate was prepared by powder metallurgy. The 4mm thick 30vo1% B_4C / 6061A1 neutron absorber plate was butt-welded by friction stir welding (FSW), and a well-formed weld was obtained. Nanoindentation method was used to study the mechanical properties of micro-zone in weld zone (WZ), TMAZ (heat affected zone), HAZ (heat affected zone) and BM (base metal) of FSW welded joint. Tensile properties were tested. Scanning electron microscope (SEM) was used to characterize the microstructure and tensile fracture of the indentation. The results show that in the same area, the hardness and elastic modulus of the micro-zone decrease with the distance d (d <11μm) from the particle / matrix interface. The values of WZ, TMAZ, BMZ and HAZ in the hardness and elastic modulus of different regions after being averaged are 28.10% and 25.14% respectively in WZ, TMAZ, HAZ and BM, 31.76% and 29.30% respectively. The reason for the difference in performance in different regions of the welded joint is that the strength of the FSW joint reaches 85.7% of the base metal and the fracture site is in the HAZ region due to the difference of plastic deformation and thermal cycling in different regions in the FSW process.