Effects of B on the Structure and Properties of Lead-Tin Bronze Alloy and the Mechanism of Strengthening and Toughening

Abstract

High lead–tin bronze is widely used in the selection of wear-resistant parts such as bearings, bearing bushes, aerospace pump rotors, turbines, and guide plates because of its excellent wear resistance, thermal conductivity, fatigue resistance, and strong load-bearing capacity. At present, high lead–tin bronze is used as a material for bimetal cylinders, which cannot meet the requirements of high-strength, anti-wear in actual working conditions under high temperature, high speed, and heavy load conditions, and is prone to de-cylinder, cylinder holding, copper sticking, etc. The reason for the failure of cylinder body parts is that the strength of copper alloy materials is insufficient, the proportion of lead in the structure is serious, and the wear resistance of the material is reduced. Therefore, it has important theoretical significance and application value to carry out research on the comprehensive properties of high-performance lead–tin bronze materials and reveal the strengthening and toughening mechanism. In this paper, The ZCuPb20Sn5 alloy is taken as the main research object, and the particle size, microstructure, mechanical properties, and friction of lead particles in ZCuPb20Sn5 alloy are systematically studied after single addition of B in ZCuPb20Sn5 alloy liquid. This paper takes ZCuPb20Sn5 alloy as the research object to study the effect of adding B on the morphology, microstructure, mechanical properties, and friction and wear properties of ZCuPb20Sn5 alloy lead particles, and discusses the strengthening and toughening mechanism of ZCuPb20Sn5 alloy under the action of B, and prepares a double high-performance lead–tin bronze alloy for metal cylinders. The main research results are as follows: The addition of B elements has an obvious refining effect on the α (Cu) equiaxed grains and lead particles in ZCuPb20Sn5 alloy. The average size of lead particles decreases from 30.0 µm to 24.8 µm as the B content increases from 0 wt.% to 0.1 wt.%. The reason for grain refinement is that B is easily concentrated at the grain boundary during the ZCuPb20Sn5 alloy solidification process, which affects the diffusion of solute atoms at the solidification interface, inhibits the grain growth, refines the grain, and hinders the sinking and homogenizes distribution between dendrites of lead; the tensile strength of the ZCuPb20Sn5 alloy improves. Relatively without B, when the addition of P is 0.1 wt.%, the tensile strength is the largest at 244.04 MPa, which enhances 13%; the maximum hardness gets 75.0 HB, which enhances 13.6%, as well as elongation get the maximum value at 17.2%. The main mechanism is that the addition of B forms a high melting point submicron Ni4B3 phase in the lead–tin bronze alloy. The Ni4B3 phase is dispersed in the matrix and strengthens the matrix. With the increase in B content (more than 0.1 wt.%), the Ni4B3 phase changes from sub-micron degree granular to micron degree block-like, and some defects such as shrinkage and porosity appear in the structure, resulting in a decrease in mechanical properties.

Study on the Bronze Weapons Excavated from Xichuan, China

“…Instead, it exists as a separate phase. When uniformly dispersed in fine particles between the dendrites, lead maximizes the melting point reduction, improves the fluidity, and increases the wear resistance while maintaining a high mechanical performance [18]. This allows intricate artifacts to be cast with greater ease.…”

Effect of ore heterogeneity on the ball mill wear rate during a grinding process at gold mines of Saudi Arabia (KSA)

“…Thus, the higher its rate in the ball is, the lower its efficiency is, meaning that it does not fulfil its function [3], [4]. For this reason, some researchers were interested in improving the properties of wear resistance using high-entropy alloys (HEAs) [5], a lead-bronze/steel bimetal composite [6], alumina-toughened-zirconia materials [7], lead-tin bronze alloy [8] etc. Fernández-Álvarez et al [9] revealed that adding nanosilica to milling process makes the epoxy-matrix coatings degrade chemically less than the non-reinforced ones under irradiation and thus wear resistance.…”

Effect of Bi Content on the Microstructure, Mechanical and Tribological Properties of Cu-Sn Alloy

“…As an excellent friction-reduction material, lead-tin bronze (Pb > 5 wt.%), with high strength, high hardness and good wear resistance, is widely used in bimetallic cylinder blocks, bearings, axial shingles, piston pump rotors and other components that require tribological performance [1][2][3][4][5]. Pb exists commonly as a free state on the α-Cu matrix; however, a layer of Pb film will be formed on the worn surface under the friction condition due to the frictional heat production.…”