Investigation of High-strength Lead-free Machinable Cu40Zn Duplex Graphite Brasses by Powder Metallurgy

Li, Shunfeng; Imai, Hisashi; Umeda, Junko; Fu, Yabo; Kondoh, Katsuyoshi

doi:10.1080/02670836.2016.1246098

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…Hence, it is recommended to modify brass into brass metal composites (BMCs) with the introduction of reinforcement particles to increase wear resistance. [1][2][3][4][5] However, it is adequate to develop the brass surface composite by reinforcing the peripheral surface, which is vulnerable to wear. This development of surface composite over the peripheral region holds on to its inner toughness and brings down the processing cost.…”

Section: Introductionmentioning

confidence: 99%

Effect of volume fraction on microstructure and wear behavior of dual-phase brass/W surface composites fabricated via friction stir processing

Karpagarajan

Balamurugan

Vigneshwaran

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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The objective of this study is to fabricate brass matrix composites (BMCs) via friction stir processing (FSP) for enhancing the wear resistance of brass. The tungsten (W) particles ranging from 0 to 18 vol.% were reinforced in the brass (Cu-40Zn) matrix through FSP. The FSP derived exceptional homogeneous dispersion of W particles leaving no traces of agglomeration and isolation. The bonding between the interface and brass matrix was strong due to the absence of pores and undesirable compounds. Irrespective of the density gradient, FSP nullified the unfavorable effect on W dispersion in BMCs. The BMCs revealed fine-grained structures in the microstructural studies when compared to that of as-received brass, which reported an average grain size of 13 µm. Particularly, the BMC with 18 vol.% W particles showed higher reduction in the average grain size (4 µm), which was 70% less than that of as-received brass. Furthermore, the transmission electron microscopy studies recorded discontinuous dynamic recrystallization and dense dislocations with a density of 9.31 × 108/mm near the stir zone. This led to an improvement in the hardness of BMCs. The BMC with 0 vol.% of W particles reported a hardness of 142 Hv whereas the BMC with 18 vol.% W particles revealed a hardness value of 165 Hv. Moreover, there was a proportional increase in hardness concerning the increase in W particles. The presence of W particles dipped the wear rate of BMCs during sliding tests and emanated smaller wear debris than the brass matrix. The wear rate was found to be 341 × 10−5mm3/m at 0 vol.% of W particles whereas the wear rate was reduced to 185 × 10−5mm3/m at 18 vol.% of W particles. The W particles in BMCs were responsible to alter the adhesive wear into abrasive wear and upgraded the wear resistance of brass material.

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Section: Introductionmentioning

confidence: 99%

Effect of volume fraction on microstructure and wear behavior of dual-phase brass/W surface composites fabricated via friction stir processing

Karpagarajan

Balamurugan

Vigneshwaran

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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“…For example, Te reacts with Zn to form ZnTe [13], and Ti and graphite cannot be added to liquid brass by conventional casting methods and need to be added by powder metallurgy methods [11,12]. Therefore, the development of lead-free brass alloys [14,15] is still a challenging topic. The present work has been carried out with this consideration.…”

Section: Introductionmentioning

confidence: 99%

Effect of addition of tin on the microstructure and machinability of α-brass

Rajabi

Doostmohammadi

2018

Materials Science and Technology

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This study was aimed at developing lead-free brass alloys with the goal of substituting lead element with tin. For this purpose, lead-free alloys with tin were developed and the microstructure, hardness and machining behaviour of the Cu–30%Zn alloy was compared with Cu–30%Zn– x%Sn ( x = 1.2, 3.2, 5.4, 8, 11.4, 13.9, 17.4). The results showed that the addition of Sn to single-α phase brass led to the formation of duplex (α + β′) brass and then the formation of (β ′ + Ɣ ) brass both with increased hardness. In addition, the addition of Sn to Cu–30%Zn alloy led to the decrement of equivalent machining forces ( Fm), surface roughness and also the promotion of chip fragmentation due to the formation of the β ′ phase, which is an improvement in machinability.

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On the function of lead (Pb) in machining brass alloys

Johansson¹,

Alm²,

M’Saoubi³

et al. 2022

Int J Adv Manuf Technol

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Lead has traditionally been added to brass alloys to achieve high machinability, but the exact mechanisms at work are still debated. Lead-free brass alternatives could be developed if these mechanisms were better understood. Accordingly, machinability characteristics were investigated for two brass alloys with similar mechanical properties and phase composition, but with very different machining characteristics because one has 3 wt.% lead (CuZn38Pb3) while the other has only 0.1 wt.% (CuZn42). The effect of the lead was investigated using infrared temperature measurement, electron microscopy, secondary ion mass spectroscopy, quick-stop methods, and high-speed filming. Neither melting of lead nor its deposition on the tool rake surface takes place during machining thus confirming its limited lubrication and tribological effects. Instead, the main role of lead is to promote discontinuous chip formation. Lead deforms to flake-like shapes that act as crack initiation points when the workpiece material passes through the primary deformation zone. This effect prevents the development of stable tool–chip contact, thus lowering cutting forces, friction, and process temperature.

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Investigation of High-strength Lead-free Machinable Cu40Zn Duplex Graphite Brasses by Powder Metallurgy

Cited by 8 publications

References 23 publications

Effect of volume fraction on microstructure and wear behavior of dual-phase brass/W surface composites fabricated via friction stir processing

Effect of volume fraction on microstructure and wear behavior of dual-phase brass/W surface composites fabricated via friction stir processing

Effect of addition of tin on the microstructure and machinability of α-brass

On the function of lead (Pb) in machining brass alloys

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