Abstract: This study addresses the stringent operational requirements of spacecraft sealed cabinets by employing laser-arc hybrid welding (LB-HW) technology and adopting a multi-scale research approach to systematically enhance welding reliability. In terms of process optimization, COMSOL multiphysics coupling simulations were used to quantitatively analyze the influence of laser-arc interaction on the molten pool flow dynamics of 304L stainless steel for the first time. When the laser power (3.5±0.2 kW) and arc current (180±5 A) generate plasma synergy, keyhole stability improves by 40%, resulting in a weld cross-section depth-to-width ratio of 3:1. X-ray inspection revealed porosity defects of only 0.18% (ASTM E390 standard).
Reliability assessment innovatively integrates response surface methodology and Monte Carlo simulation to construct a limit state function incorporating seven variables, including heat-affected zone hardness gradient and residual stress distribution. Experimental data demonstrate that joints subjected to ultrasonic impact treatment achieve a fatigue life of 2.1×10 cycles (stress ratio R=0.1), with a reliability index β=4.32, corresponding to a failure probability two orders of magnitude lower than conventional TIG welding34. Notably, digital image correlation (DIC) technology verified that welding deformation (0.15 mm/m) deviates by less than 5% from finite element predictions5.
The current technical bottleneck lies in microstructural stability under space radiation environments. Future research will employ in-situ transmission electron microscopy (TEM) to observe hydrogen-induced crack propagation behavior, combined with Bayesian update algorithms for dynamic optimization of process windows. This study provides an experimentally validated reliability enhancement solution for next-generation space station cabinet manufacturing.