Title: Effects of density and microstructure on surface integrity of HIP materials

Authors: F.J. Sun; S.G. Qu; F. Su; Z.H. Deng

Addresses: Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material, Hunan University of Science and Technology, Xiangtan, 411201, China; Intelligent Manufacturing Institute of HNUST, Hunan University of Science and Technology, Xiangtan, 411201, China ' School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, 510640, China ' Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material, Hunan University of Science and Technology, Xiangtan, 411201, China; Intelligent Manufacturing Institute of HNUST, Hunan University of Science and Technology, Xiangtan, 411201, China ' Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material, Hunan University of Science and Technology, Xiangtan, 411201, China; Intelligent Manufacturing Institute of HNUST, Hunan University of Science and Technology, Xiangtan, 411201, China

Abstract: Ti-6Al-4V materials with different densities were prepared using hot isostatic pressing (HIP) technology. Surface integrities of the HIP materials were studied to analyse the surface integrity changing trend with density and microstructure. Due to the existence of micro-voids of the HIP material micro-hole appeared in the machined workpiece surface, which resulted in the formation of the deeper and greater micro-hole defects with decreasing material density. The serrated chip formation, different nanoindentation hardness of crystalline structures and micro-void existence had a potential to make the plastic deformation of the workpiece surface layer along the cutting direction to be different. Refined β phase and micro-void greatly affected plastic deformation of the workpiece surface layer, and the residual tensile stress was influenced by the microstructure and residual micro-void in machining of the HIP materials prepared with different HIP parameters.

Keywords: Ti-6Al-4V; hot isostatic pressing; HIP; density; microstructure; surface integrity; micro-void.

DOI: 10.1504/IJMMM.2019.103131

International Journal of Machining and Machinability of Materials, 2019 Vol.21 No.5/6, pp.357 - 374

Received: 23 Feb 2018
Accepted: 07 Jun 2018
Published online: 21 Oct 2019 *

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