Sintering Response of Aluminum 6061-TiB 2 Composite: Effect of Prealloyed and Premixed Matrix
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JMEPEG (2017) 26:4470–4480 DOI: 10.1007/s11665-017-2883-4
Sintering Response of Aluminum 6061-TiB2 Composite: Effect of Prealloyed and Premixed Matrix Mahesh Paidpilli, Gaurav Kumar Gupta, and Anish Upadhyaya (Submitted March 1, 2017; in revised form July 10, 2017; published online September 5, 2017) In the present study, Al6061-based alloy and composites were produced using powder metallurgy route. Two different kinds of base powders (prealloyed and premixed 6061Al alloy) were mixed with TiB2 particles in compositions ranging from 0 to 15 vol.%, respectively. The processed powders were compacted at 300 MPa and sintered at 620 °C under N2 atmosphere. The microstructural evolution of prealloyed and premixed 6061Al alloy, at different stages of sintering cycle, was studied using scanning electron microscope and EDS analysis. A comparative study was done between prealloyed- and premixed-based composites on the basis of densification, microstructure, hardness, transverse rupture strength and electrical conductivity as a function of TiB2 content. Results indicated that premixed-based composites have better mechanical properties than prealloyed-based composites. Keywords
6061Al alloy, 6061Al-TiB2 composite, mechanical properties, microstructure, prealloyed, premixed
1. Introduction High densification is difficult to achieve through sintering of aluminum powder because of the presence of oxide layer on Al powder surface that hinders the densification process and causes inferior mechanical properties (Ref 1, 2). To overcome the above constraint, Lumley et al. (Ref 2) reported that addition of 1 wt.% Mg is able to disrupt the oxide layer though formation of spinel structure (MgAl2O3) and thus contributes to densification. Additionally, Schaffer et al. (Ref 3) studied the effect of atmosphere in sintering of aluminum powder and reported that N2 is beneficial as compared to vacuum and argon. In recent years, aluminum-based prealloyed powders have been developed through atomization route. This aluminum-based prealloyed powder is sintered between solidus and liquidus temperature range to produce some liquid for densification through rearrangement and other diffusion mechanisms (Ref 4). Youseffi and Showaiter (Ref 5) documented that successful sintering of prealloyed 6061Al compact above solidus temperature depends on the quantity of persistent liquid formed during the sintering process. Ziani and Pelletier (Ref 6) reported that super-solidus liquid phase sintering of prealloyed 6061Al alloy has improved sinterability and mechanical properties. Aluminum-based alloys offer a unique combination of properties such as high strength to weight ratio, better workability, high electrical conductivity and resistance to corrosion, but have poor wear resistance (Ref 7). To improve
Mahesh Paidpilli and Anish Upadhyaya, Department of Material Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India; and Gaurav Kumar Gupta, Materials Science and Engineering Department, CSIR-AMPRI, Bhopal, MP 462024, India. Contact e-mai
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