The instantaneous evolutions of the molten pool and plasmas during the pulse fiber laser welding of pure zirconium (Zr) under different high pressure environment were explored. Furthermore, the mechanism and influence law of the increase of the pressure on the weld penetration of pure Zr were analyzed. The result indicated that the weld penetration of pure Zr significantly reduced with the ambient pressure’s growth. That is because of it could lead to the strengthening of the shielding effect of plasmas generated during laser welding on laser energy and improve the evaporating temperature required to produce the recoil pressure. The research result can enrich the theory on laser process under hyperbaric conditions and is favorable for the development of the laser manufacturing technology in the nuclear industry.

探索了在不同高压环境下纯锆（Zr）脉冲光纤激光焊接过程中熔池和等离子体的瞬时演变。此外，分析了压力增加对纯Zr焊缝熔深的影响机理和影响规律。结果表明，随着环境压力的增加，纯Zr的焊缝熔深显着降低。这是因为它可能导致增强激光焊接过程中产生的等离子体对激光能量的屏蔽效果，并提高产生反冲压力所需的蒸发温度。研究结果可以丰富高压条件下的激光加工理论，有利于核工业中激光制造技术的发展。