This study examines how hydrogen embrittlement (HE) affects strain-induced martensitic transformation and stress corrosion cracking (SCC) in hydrogen-charged additively manufactured 316LN stainless steel under acidic conditions. Microstructural and failure analysis using SEM, EBSD, and X-ray techniques revealed that HE significantly increases α′-martensite formation (from ~8 to 15 vol.%), leading to brittle fracture marked by fractured martensite and slip traces. The α′-phase acted as a key driver of failure by creating anodic, high-strain regions prone to cracking. In acidic environments, its preferential dissolution further accelerated localized corrosion compared to the γ-phase
