Researchers Develop Crack-Free Metal Technology for High-Heat Industries

Joining stainless steel and Inconel has traditionally been challenging because the two materials have different chemical compositions, melting points and thermal expansion properties.

Researchers at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, have developed a crack-free bi-metallic structure that could reduce India's dependence on costly imported superalloys while improving the performance of components used in aerospace, nuclear and energy sectors.

The innovation uses laser-based powder bed fusion (PBF-LB/M), an advanced additive manufacturing process that successfully joins stainless steel (SS316L) with the Inconel 718 nickel-based superalloy, two materials that are extremely difficult to weld using conventional methods. The research was carried out by S. Narayanaswamy, Gururaj Telasang, Nokeun Park and Ravi Bathe of ARCI, an autonomous institute under the Department of Science and Technology (DST). Their findings have been published in the journal Progress in Additive Manufacturing.

Stronger, crack-free interface improves industrial performance

Joining stainless steel and Inconel has traditionally been challenging because the two materials have different chemical compositions, melting points and thermal expansion properties. Conventional welding often results in cracks, porosity and weak interfaces that limit the reliability of critical components. Using additive manufacturing, the ARCI team fabricated stainless steel directly onto a surface-prepared Inconel plate, producing a defect-free interface without visible cracks or porosity.

Tests showed the interface achieved a peak hardness of around 310 HV and an ultimate tensile strength of 550 ± 30 MPa. During tensile testing, the material failed on the softer stainless steel side rather than at the joint, demonstrating the exceptional strength and integrity of the bi-metallic interface.

Wide applications across energy and aerospace sectors

The technology could be used to manufacture advanced components for gas turbines, boiler tubes, heat exchangers, nuclear reactors, ultra-supercritical thermal power plants, oil and gas facilities, and other industrial systems where different parts of a component operate under varying temperatures and stress levels.

In aerospace applications, the stainless steel section can provide structural strength, while the Inconel portion withstands extreme temperatures. The use of additive manufacturing also allows engineers to place expensive superalloys only where they are needed, reducing material costs while improving performance and lowering India's reliance on imported high-value alloys.

The breakthrough is expected to support the development of next-generation multi-material components for demanding industrial environments while strengthening India's advanced manufacturing capabilities.