Influence Mechanism of Heat Treatment on Ultra-precision Turning Characteristics of Additively Manufactured AlSi10Mg Parts

doi:10.3901/JME.2022.19.315

Abstract

Abstract: The surface quality of AlSi10Mg alloy fabricated directly by selective laser melting (SLM) technology generally shows insufficient surface quality, which cannot meet the stringent requirements of some industries for high accuracy in precision engineering. To this end, ultra-precision machining provides a promising post-processing solution for augmented surface quality on SLM parts. In this study, diamond tools were used to investigate the micro-cutting characteristics of as-built, annealed, solution-treated and ageing-treated SLM-AlSi10Mg alloy. The influence of microstructure evolution and cutting parameters on the ultra-precision machining characteristics of AlSi10Mg alloy was discussed. The effect of heat treatment on cutting force, cutting surface quality and chip morphology was revealed aiming to identify the methods to quickly and efficiently improve the surface quality of SLM parts to achieve mirror-surface finishing. The results show that the microstructure of the as-built AlSi10Mg alloy is dominated by a micron-level cellular structure, and its micro Vickers hardness and cutting force are greater than that of the heat-treated sample. The cutting force is simultaneously affected by the microstructure and mechanical properties of the alloy. The surface quality of the grooves of the as-built sample is the best, followed by annealed, ageing-treated and solution-treated samples. The large Si particles formed after high-temperature heat treatment will lead to brittleness of the chips and reduce the X-axis cutting force. Increasing the depth of cut and cutting speed will cause the increase in cutting force and poor surface quality, where the effect of the former factor is more pronounced. Through the present study, the best surface roughness has been improved to 11.2 nm by 3 orders of magnitude from ～10 µm of the as-built sample by SLM. This study provides a theoretical and application reference for the improvement of the surface quality of SLM aluminium alloy parts to the nanometric level.

Key words: selective laser melting, AlSi10Mg alloy, ultra-precision machining, microstructure, machinability

CLC Number:

TG519

BAI Yuchao, CHEN Jie, LIU Linqing, WEI Xiongmian, WANG Di. Influence Mechanism of Heat Treatment on Ultra-precision Turning Characteristics of Additively Manufactured AlSi10Mg Parts[J]. Journal of Mechanical Engineering, 2022, 58(19): 315-330.

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