Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Xianjie Yuan,Mingqi Tang,Zhaojun Tan,Haiqing Yin,Zaiqiang Feng,Xuanhui Qu,Zhenwei Yan

doi:10.3390/met11020218

Abstract

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

Highlights

The powder metallurgy (PM) route provides lower energy consumption, higher material utilisation and excellent machinability in aluminium [1]
The theoretical density of Al-based alloy was 2.92 gcm−3 [20], and, with the increasing of sintering temperature, the sintered density gradually increased
During the sintering process of the green, with the increasing of sintering temperature, the powder particles boundary developed from poor mechanical bonding to strong metallurgical bonding, and internal pores of the green become smaller or disappear

Summary

Introduction

The powder metallurgy (PM) route provides lower energy consumption, higher material utilisation and excellent machinability in aluminium [1]. PM technology can present a homogeneous microstructure with little segregation compared with the casting method [2]. Al-based PM alloy is currently an area of rapid development. The automotive industry is the main consumer of Al-based PM parts because of the lightweight and cost-effective nature of this process [3]. Al-based PM camshaft bearing caps were firstly introduced with the commercial inception of this technology in the mid-1990s. Al-based PM materials have been developed to expand the application of the automobile field [4,5,6]. Efforts have largely addressed the development of PM counterparts to wrought or cast alloys that span a broad range of properties [7,8,9]

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Conclusion