冷拉变形及退火对新型70Cu-1Sn黄铜组织和性能的影响

Influence of Cold Drawing Deformation and Annealing on Microstructure and Property of New 70Cu-1Sn Brass

本文研究了不同冷拉变形量和退火处理对新型70Cu-1Sn黄铜显微组织和性能的影响。结果表明:在铜锌二元合金中加入少量Sn、Al、P、Ni合金元素构成了新型的70Cu-1Sn合金,合金元素以固溶体的形式存在于晶粒内部,合金为α单相组织。随着冷拉拔变形量增大,沿着冷拉拔方向晶粒的变形程度逐渐增大,当变形量达43%时出现片状纤维组织;衍射峰宽化程度逐渐增大,没有发生相变或者有序化转变。加工硬化过程中合金的硬度、抗拉强度、脱锌腐蚀深度和腐蚀电流密度快速增加,但其伸长率、腐蚀电位逐渐降低,导致合金耐腐蚀性逐渐变差。退火态的合金以等轴晶为主,晶粒内部有一定数量的退火孪晶,其脱锌腐蚀深度约为17μm,其脱锌腐蚀深度远小于加工率43%的合金的155μm,其腐蚀电位最高且电流密度最小。

The influences on the microstructure and property of new 70 Cu-1Sn brass in different cold drawing deformation and annealing process were studied. Results show that adding a small amount of Sn、Al、P and Ni in Cu-Zn binary system can give a new type of 70Cu-lSn brass, in which four alloying elements totally exist in each polycrystalline grain as a solid solution of a-phase. With the increase of cold drawing deformation, the deformation degree of the grains increases along the cold drawing direction, and some laminar fiber tissue form as the drawing deformation reaches 43%; in addition, the width of each diffraction peak from XRD also increases gradually, and no phase transformation or ordering is foundoccurring. During the process of work hardening, hardness,tensile strength, depth of dezincification corrosion and current density increase quickly, however elongation and open circuit potential gradually reduce, which make corrosion resistance of alloy become worse gradually. The composition of alloy annealing is mainly isometric crystal, and grains contain some annealing twins, the depth of dezincification corrosion of alloy annealing is about 17μm, which is far less than the 155μm of alloy cold drawing deformation of 43%, open circuit potential reaches the highest and current density is the minimal.