静磁场深冷处理对铝黄铜组织和性能的影响

Effect of Simultaneous Magnetic Field and Deep Cryogenic Treatment on the Microstructure and Mechanical Properties of Aluminum-brass

对铝黄铜进行静磁场条件下不同时间的深冷处理,并与初始试样和同时间单独深冷试样进行对比分析,结果表明静磁场能够进一步提高铝黄铜的强韧性。在T=24h时,MDCT试样的强韧性最好,其抗拉强度为602.5 MPa,延伸率为7.2%,较初始样分别提高了6.4%和53.2%,较DCT24试样分别提高3.1%和28.6%。分析原因在于从深冷回复到室温过程中铝黄铜发生了回复再结晶,起到了细晶强化作用;同时基于磁致塑性效应,位错运动灵活性增加,有助于提高延伸率和塑性变形能力。另外,静磁场在深冷过程中起到抑制铝黄铜α→β相转化和促进γ相转变的作用,使得MDCT试样平均晶粒尺寸较DCT试样大。

The effect of simultaneous magnetic field and deep cryogenic treatment on the structure and mechanical properties of aluminum brass subjected to deep cryogenic treatment was investigated.The results show that the static magnetic field can further improve the strength and toughness of the aluminum-brass.When T=24h,the test samples named MDCT（magnetized-deep cryogenically treated samples）have the best tensile strength（602.5 MPa）and elongation（7.2%）which increase by 6.4% and 53.2%compared with the initial sample,and increase by 3.1% and 28.6% respectively compared with DCT（deep cryogenically treated samples）.The reason for the property improvement is that during the reversion of test sample from deep cryogenic condition to room temperature,the dynamic recrystallization occurs,which play an important role in grain refinement strengthening effect.At the same time,based on the magnetoplasticity effect,it is easier for the dislocation to move which is beneficial to improve the capability of elongation and plastic deformation.In addition,under the condition of static magnetic field,the conversion rate ofα-phase toβ-phase in Al-brass has been reduced,and the conversion rate ofγ-phase increased.Besides,the average grain size of MDCT is bigger than DCT.