**Executive Summary**
Researchers at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI) have developed a crack-free bi-metallic structure using laser-based powder bed fusion (PBF-LB/M) additive manufacturing. This breakthrough, published on 02 July 2026, enables the joining of stainless steel (SS316L) and Inconel superalloy (IN718) to reduce reliance on expensive superalloy imports. The technology allows for the strategic placement of high-performance materials in critical zones of industrial components.
**Key Points / Main Content**
**Technological Innovation**
* Utilizes laser-based powder bed fusion (PBF-LB/M) to build SS316L directly onto surface-ground IN718 plates.
* Achieves a compositionally graded, mechanically robust, and crack-free interface without the porosity common in conventional welding.
* Addresses historical challenges of joining dissimilar metals, such as solidification cracking and the formation of brittle intermetallics.
**Mechanical Performance**
* The bi-metallic interface demonstrated a peak hardness of approximately 310 HV.
* Recorded an ultimate tensile strength (UTS) of 550 ± 30 MPa.
* Structural integrity was validated as mechanical failure occurred on the softer SS316L side rather than at the bi-metallic junction.
**Strategic and Economic Benefits**
* Reduces overall use of expensive superalloys by limiting their application to regions of extreme thermal exposure.
* Decreases national dependency on imported superalloys.
* Enables the fabrication of complex internal structures and multi-material components for demanding environments.
**Impact Analysis**
**Aerospace Industry**
**Impact:** Manufacturers can now produce components where a steel side serves as the load-bearing element while the Inconel side provides high-temperature resistance for sections exposed to up to 2000°C.
**Action Required:** Integrate additive manufacturing into the design of gas turbines and internal structures to optimize material placement and improve component performance.
**Energy Sector (Nuclear, Thermal, and Coal-fired Power Plants)**
**Impact:** Provides a solution for components like boiler tubes and heat exchangers in ultra-supercritical (USC) plants where sections face varying temperature and stress conditions.
**Action Required:** Evaluate the adoption of these bi-metallic structures to enhance the durability and efficiency of advanced energy systems.
**Oil and Gas Processing Industries**
**Impact:** Access to components that simultaneously offer high corrosion resistance (from stainless steel) and high-temperature strength (from nickel-based superalloys).
**Action Required:** Utilize this technology for hardware operating in environments requiring dual-material properties.
**Research and Development Communities**
**Impact:** Provides a validated methodology for achieving superior interfacial integrity in multi-material additive manufacturing.
**Action Required:** Reference the study published in *Progress in Additive Manufacturing* (DOI: 10.1007/s40964-025-01036-1) for further technical development and scaling.
Key Entities Referenced
International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad: An autonomous institute under the Department of Science and Technology that developed the crack-free bi-metallic structure to reduce superalloy import dependency.
Department of Science and Technology (DST): The central government department that oversees and supports the research initiative into additive manufacturing for industrial components.
Ministry of Science & Technology: The primary ministry responsible for the scientific breakthrough aimed at enhancing self-reliance in aerospace, nuclear, and power sectors.
Ministry of Science & Technology
Breakthrough in superalloy bi-metallic structures
through additive manufacturing can reduce
import of super-alloys
प्रव तथ: 02 JUL 2026 4:18PM by PIB Delhi
A crack-free bi-metallic structure developed by researchers using a technique called laser-based powder
bed fusion (PBF-LB/M) additive manufacturing can help in reducing the overall use of expensive
superalloys thereby reducing the import dependency.
Stainless steels and nickel-based super alloys are widely used in aerospace, nuclear, as well as thermal
power plants. Certain regions of a gas turbine may experience temperatures as high as 2000°C, while
adjacent sections are exposed to lower temperatures during service conditions. Therefore, combining
stainless steel (good toughness and corrosion resistance) with nickel-based superalloys (excellent high-
temperature strength and creep resistance) in a single component is technologically attractive.
However, conventional welding of Stainless steel (SS316L) and the Inconel superalloy (IN718) is
challenging due to differences in chemical composition, melting temperatures, and thermal expansion
coefficients. These differences often lead to solidification cracking, porosity, segregation of Nb/Mo-rich
phases, and formation of brittle intermetallics. While joining dissimilar metals is not uncommon,
achieving a crack-free, compositionally graded, mechanically robust interface using powder bed fusion,
with tensile validation across the interface, remains challenging.
Research by the International Advanced Research Centre for Powder Metallurgy and New Materials
(ARCI), Hyderabad, an autonomous institute of the Department of Science and Technology (DST)
addresses that gap.
Fig: (a) bimetallic structure and the mechanical behaviour is shown in terms of (b) micro-hardness and
(c) tensile test across the bi-metallic interface.
The bi-metallic structure SS316L was fabricated using a laser-based powder bed fusion system through
additive manufacturing and building directly onto the surface-ground IN718 plate with no visible cracks
or porosity at the interface. The material exhibited a peak hardness of approximately 310 HV at the
interface and an ultimate tensile strength (UTS) of 550 ± 30 MPa, with failure occurring on the softer
SS316L side, away from the bi-metallic junction, demonstrating superior interfacial integrity.This development, by the team consisting of S. Narayanaswamy, Gururaj Telasang, Nokeun Park and Ravi
Bathe published in the journal Progress in Additive Manufacturing, enables the fabrication of multi-
material components for demanding industrial environments. Potential applications include boiler tubes,
heat exchangers for nuclear and ultra-supercritical (USC) coal-fired power plants, and advanced energy
systems, where different sections of a component experience varying temperature and stress conditions.
The technology is also relevant for nuclear reactors and oil and gas processing industries, where corrosion
resistance and high-temperature strength are simultaneously required.
In the aerospace sector, a bi-metallic structure can be used, with a steel side serving as the load-bearing
component, while the Inconel side provides high-temperature resistance. Additive Manufacturing also
opens the door to internal structures, enabling the strategic placement of superalloys only in regions
subjected to extreme thermal exposure and improving component performance.
Publication link: https://doi.org/10.1007/s40964-025-01036-1.
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