Abstract
Stelite-6/Inconel 718 functionally gradient materials (FGM) is a heat-resisting functional gradient material with excellent strength performance under ultra-high temperatures (650–1100 °C) and, thus, has potential application in aeronautic and aerospace engineering such as engine turbine blade. To investigate the effect of initial temperature on the microstructure and properties of laser metal deposition (LMD) functional gradient material (FGM), this paper uses the LMD technique to form Stelite-6/Inconel 718 FGM at two different initial temperatures: room temperature and preheating (300 °C). Analysis of the internal residual stress distribution, elemental distribution, microstructure, tensile properties, and microhardness of 100% Stelite-6 to 100% Inconel 718 FGM formed at different initial temperatures in a 10% gradient. The experimental results prove that the high initial temperature effectively improves the uneven distribution of internal residual stresses. Preheating slows down the solidification time of the melt pool and facilitates the escape of gases and the homogeneous diffusion of elements in the melt pool. In addition, preheating reduces the bonding area between the gradient layers, enhancing the metallurgical bonding properties between the layers and improving the tensile properties. Compared with Stellite-6/Inconel 718 FGM formed at room temperature, the mean yield strength, mean tensile strength, and mean elongation of Stellite-6/Inconel 718 FGM formed at 300 °C are increased by 65.1 Mpa, 97 MPa, and 5.2%. However, the high initial temperature will affect the hardness of the material. The average hardness of Stellite-6/Inconel 718 FGM formed at 300 °C is 26.9 HV (Vickers hardness) lower than that of Stellite-6/Inconel 718 FGM formed at 20 °C.
Highlights
Stellite-6 is the most widely used wear-resistant cobalt-based alloy and is considered the industry standard for general wear applications, offering excellent resistance to deformation over a wide temperature range and maintaining a reasonable level of hardness at 500 ◦ C
Ni/Co-based functional graded material is an advanced metal matrix composite composed of multi-component alloys and strengthening phases through continuous gradual compounding, which can form hot end parts such as aero-engine turbine blades by laser cladding deposition technology, and has great potential in aerospace applications
The aim of this paper is to investigate issues such as cracking defects arising from The aim of this paper is to investigate issues such as cracking defects arising from the formation of Stellite-6/Inconel 718 functionally gradient materials (FGM) at room temperature based on the laser metal deposition (LMD)
Summary
Stellite-6 is the most widely used wear-resistant cobalt-based alloy and is considered the industry standard for general wear applications, offering excellent resistance to deformation over a wide temperature range and maintaining a reasonable level of hardness at 500 ◦ C. Ni/Co-based functional graded material is an advanced metal matrix composite composed of multi-component alloys and strengthening phases through continuous gradual compounding, which can form hot end parts such as aero-engine turbine blades by laser cladding deposition technology, and has great potential in aerospace applications. As a common additive manufacturing technology, laser metal deposition (LMD) has received extensive attention and research because of its unique advantage. As a common additive manufacturing technology, laser metal deposition (LMD) has received extensive attention and research because of its unique advantage in forming FGM parts [8]. During the LMD process, several kinds of in formingalloy
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