Investigating the Linear Thermal Expansion of Additively Manufactured Multi-Material Joining between Invar and Steel.

Area of Science:

• Materials Science and Engineering
• Additive Manufacturing
• Thermal Properties of Materials

Background:

• Multi-material tooling often requires precise control over thermal expansion.
• Traditional materials may not meet the demanding CTE requirements for advanced applications.
• Additive manufacturing offers novel approaches for creating customized material properties.

Purpose of the Study:

• To investigate the linear thermal expansion properties of Invar M93 and A36 steel composites.
• To assess the feasibility of using additively manufactured Invar M93 to reduce the coefficient of thermal expansion (CTE) in multi-material tooling.
• To analyze the impact of material interfaces and elemental diffusion on thermal expansion.

Main Methods:

• Additive manufacturing of Invar M93 beads onto an A36 steel base plate using a fiber laser system.
• Measurement of CTE using a thermomechanical analyzer (40 °C–150 °C).
• Elemental composition analysis via energy dispersive X-ray spectroscopy.
• Strain gauge measurements on machined multi-material samples heated in an oven (40 °C–160 °C).

Main Results:

• CTE of steel and interface samples were comparable to A36 steel, with deviations attributed to element diffusion.
• Additively manufactured Invar beads exhibited significantly lower CTE values (2.09–10.40 μm/m-K).
• Machined Invar surfaces showed an average of 42% less expansion than steel surfaces in multi-material tools.

Conclusions:

• Additively manufactured Invar M93 effectively reduces the coefficient of thermal expansion in multi-material components.
• The study validates the use of Invar M93 for developing advanced multi-material tooling with tailored thermal properties.
• Understanding element diffusion at the material interface is crucial for predicting thermal behavior.