Hot isostatic pressing of additively manufactured metallic components: A critical review on microstructure, mechanical, and corrosion properties
Yahya Aghayar, Ayda Shahriari, Parisa Moazzen, Mohsen Mohammadi
Abstract
Laser Powder Bed Fusion (LPBF) has established itself as a leading additive manufacturing (AM) technology, offering unparalleled design freedom and the ability to fabricate complex geometries with minimal material waste. However, process-intrinsic defects such as porosity, microcracks, and anisotropic microstructures continue to limit the structural integrity and long-term performance of LPBF components in critical applications. Among available post-processing strategies, Hot Isostatic Pressing (HIP) has emerged as the most effective approach for mitigating these challenges. This review examines the role of HIP in enhancing the performance of LPBF metals. The fundamental principles of HIP temperature, pressure, dwell time, and cooling rate, are summarized alongside standard practices established by ASTM guidelines and recent experimental advances. The impact of HIP on defect elimination, microstructural homogenization, and property modification is critically analyzed across diverse alloy systems including stainless steels, titanium alloys, nickel-based superalloys, copper, and high-entropy alloys. Evidence from mechanical, physical, and electrochemical studies demonstrated that HIP not only could lead to near-full densification and improved fatigue resistance but also can enhance thermal/electrical conductivity and corrosion behavior in corrosive media such as nuclear and marine environments. HIP represents a crucial enabler for qualifying LPBF components for deployment in aerospace, marine, energy, and biomedical sectors, bridging the gap between additive manufacturing research and industrial adoption.