Mechanical and Scratch behaviour of TiAlN Coated and 3D Printed H13 Tool Steel

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ABSTRACT

This investigation focuses on the manufacturing of H13 tool steel samples using the selective laser melting (SLM) process. The sample with the highest part density (99% relative density) and lowest porosity was obtained with 733.3 J/mm³ volumetric energy density and other process parameters such as 203 W of laser power, 92.3 m/s of scan speed, 50 µm of layer thickness, and 60 µm of hatch spacing. The SLM sample was tempered at 550°C and dwelled for 2 hours, followed by furnace cooling. Tempering transformed the retained-austenite into tempered austenite, ferrite, and few carbides with BCC structure. Further, TiAlN coating was deposited over both the samples (as-SLM and tempered-SLM) resulting in improved surface quality and mechanical properties. Microhardness of the as-SLM sample was improved by 1.51 and 3.99 times on post-tempering and coating deposition, respectively. Moreover, the ratios of hardness and Young’s modulus (H/E and H³/E²) also got improved. What is more, in the adhesion test, typically, three different cracks (parallel crack, angular crack and transverse crack) were observed as the failure mechanism of coating with both the samples. Nevertheless, TiAlN coating showed better adhesion with tempered-SLM sample compared to the as-SLM sample.

KEYWORDS:

• Additive manufacturing
• slm method
• ✚-gas-atomised H-13 powder
• microhardness
• scratch test

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).