Hot Deformation Behavior and Processing Map of High-Strength Nickel Brass

Qiang Liang,Xianming Zhang,Ping Li,Xin Liu

doi:10.3390/met10060782

Qiang Liang, Xianming Zhang + Show 2 more

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https://doi.org/10.3390/met10060782

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Abstract

The flow behavior of a new kind of high-strength nickel brass used as automobile synchronizer rings was investigated by hot compression tests with a Gleeble-3500 isothermal simulator at strain rates ranging from 0.01 to 10 s−1 and a wide deformation temperature range of 873–1073K at intervals of 50 K. The experimental results show that flow stress increases with increasing strain rate and decreasing deformation temperature, and discontinuous yielding appeared in the flow stress curves at higher strain rates. A modified Arrhenius constitutive model considering the compensation of strain was established to describe the flow behavior of this alloy. A processing map was also constructed with strain of 0.3, 0.6, and 0.9 based on the obtained experimental flow stress–strain data. In addition, the optical microstructure evolution and its connection with the processing map of compressed specimens are discussed. The predominant deformation mechanism of Cu-Ni-Al brass is dynamic recovery when the deformation temperature is lower than 973 K and dynamic recrystallization when the deformation temperature is higher than 973 K according to optical observation. The processing map provides the optimal hot working temperature and strain rate, which is beneficial in choosing technical parameters for this high-strength alloy.

Highlights

Hot deformation is a complex plastic deformation processing method and can be affected by many factors, such as strain rate, deformation and microstructure
It can be seen that the deformation temperature and strain rate have important effects on true flow stress under all deformation conditions
The curves clearly show that true stress increases when the deformation temperature is decreased from 1073 to 873 K or the strain true stress increases when the deformation temperature is decreased from 1073 to 873 K or the rate is increased from 0.01 to 10 s−1, which indicates that Cu-Ni-Al nickel brass is a deformation strain rate is increased from 0.01 to 10 s−1, which indicates that Cu-Ni-Al nickel brass is a temperature- and strain rate-sensitive material

Summary

Introduction

Hot deformation is a complex plastic deformation processing method and can be affected by many factors, such as strain rate, deformation and microstructure. High-strength brass is often chosen as a component material because of its good strength, toughness, and corrosion resistance and remarkable wear resistance. High-strength brass contains an α + β or β phase which may contain some conditional elements, such as nickel, aluminum, iron, and silicon. These additions enhance the strength property due to solute strengthening, precipitation strengthening, and grain refinement [1,2]. In the case of nickel brass, used to fabricate synchronizer ring gears, it has a narrow deformation temperature range in which it deforms and a fragile temperature interval, which may lead to defects in the final component after deformation. A comprehensive study on hot compression behavior and workability is required to successfully obtain qualified products without any deformation defects

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