دانلود رایگان ترجمه مقاله بررسی جوشکاری TIG کامپوزیت آلومینیوم ماتریس تقویت شده با SiCp (نشریه الزویر 2009)

بررسی جوشکاری TIG کامپوزیت SiCp-آلومینیوم تقویت شده-ماتریس با استفاده از گاز مخلوط شده محافظ و پرکننده Al-Si

Investigation on TIG welding of SiCp-reinforced aluminum–matrix composite using mixed shielding gas and Al–Si filler

Abstract

Using He–Ar mixed gas as shielding gas, the tungsten inert gas (TIG) welding of SiCp/6061 Al composites was investigated without and with Al–Si filler. Welded joint with filler were submitted to tensile tests. The microstructure and fracture morphology of the joint were examined. The results show that adding 50 vol.% helium in shielding gas improves the arc stability, and seams with high-quality appearance are obtained when the Al–Si filler is added. In addition, the interface reaction between SiC and matrix is greatly suppressed when using Al–Si filler. The microstructure of the welded joint displays non-uniformity with many SiC particles distributing in the weld center. The average tensile strength of weld joints with Al–Si filler is 70% above that of the matrix composites under annealed condition.

1 Introduction

Aluminum–matrix composites have wide applications, e.g. in the aerospace and automobile industries, due to their high specific strength, rigidity, wear resistance and good dimensional stability compared with unreinforced alloys [1–4]. One of the aluminum–matrix composite families with higher potential application, thanks to their excellent specific properties and acceptable fabrication costs, is constituted of medium- or high-strength aluminum alloys (i.e. 2xxx and 6xxx series) reinforced with SiC particles [4]. However, its further application and development are faced with the problem of poor weldability, caused by the great difference between aluminum–matrix and reinforcement in physical and chemical properties [5].

In recent years, the results of much research work have been published proposing the application of solid-state bonding techniques (diffusion bonding, friction welding, etc.) to solve those problems [2,5]. The weldability of SiC particle-reinforced aluminum–matrix composites has been investigated in friction welding [6]. Both inertia friction welding and continuous-drive friction welding can produce high-quality joints with uniform microstructures and promising mechanical properties, which are to date regarded as the most promising joining techniques [2]. Diffusion welding has been studied widely, including solid-state diffusion welding without interlayer. Transient liquid-phase dif- fusion bonding has also been used to join SiC particle-reinforced aluminum–matrix composites, and the results were favorable [2–6].

Fusion welding is the most flexible and versatile welding technology. Extensive investigation on welding of SiC particlereinforced aluminum–matrix composites with high-power laser beam and electron beam has been conducted [7,8] in order to produce ideal microstructure and joint strength. However, the typical limitations of the procedures mentioned above as regards production capacity and equipment costs make it necessary to reconsider the possibility of the application of more productive welding processes [2]. Traditional tungsten inert gas (TIG) and metal inert gas welding techniques have been applied to join SiC particle-reinforced aluminum–matrix composites [2,9]. Their industrial application is much limited owing to the high viscosity of the molten pool, the segregation and agglomeration of reinforcing particles, and especially the serious interface reaction between SiC particle and aluminum–matrix, leading to less acceptable mechanical properties. This paper describes an experimental research on the TIG weldability of SiC-reinforced 6061 aluminum alloy protected with helium–argon mixed gas.