Effects of powder feeding rate on porosity and tensile strength of powder feeding laser welded Al-30wt.% B4C composite with the addition of Al powder

Abstract

Al-B4C metal matrix composite is an advanced neutron absorption material. In order to obtain a wider application in spent nuclear fuel storage and transport, the welding technique is essential for Al-B4C composites. In this paper, powder feeding laser welding (PFLW) method was used to weld Al-30wt.% B4C composite. During the experiments, Al powder was used as the filler metal, the effects of powder feeding rate on porosity, neutron shielding ratio and tensile strength of the joints were investigated by using micro-CT (micro computed tomography), OM, SEM and TEM. It is found that PFLW has a significant weld porosity suppression effect, and a joint efficiency (UTS) of 87% is obtained in PFLW of Al-30wt.% B4C composite with the powder feeding rate of 1.2 g/min. The neutron shielding ratio of the joint reduced by 3% due to the volume ratio of AlB12C2 (a B-rich reaction product) reduced by 7.6% when the powder feeding rate is 1.2 g/min. The results illustrate the great potential of PFLW in welding Al-B4C composites.