摘要
通过对施加30%～70%的冷变形量的Cu-1.4Ni-1.2Co-0.6Si合金时效过程中的显微硬度及导电率规律分析和透射电镜观察,发现固溶合金时效前冷变形可加速时效初期第二相析出,导电率得以快速上升。如合金经过30%形变400℃时效1 h后导电率可达43%IACS,而固溶后直接时效为40.7%IACS。经过冷轧-时效后,沿位错分布着许多细小的析出相,使位错在时效过程中运动困难,同时合金内形成了高密度的位错,析出相弥散细小分布在基体中,故可以获得较高的显微硬度,如经30%形变于400℃时效2 h其显微硬度可达HV223,而未加形变直接时效合金的显微硬度为HV202。形变析出与再结晶过程中再结晶时间tR和时效析出时间tP取决于形变量和时效制度,在一定的形变量和较高的时效温度的条件下,合金内晶粒易发生再结晶。合金70%变形500℃时效2 h,由于基体中产生高密度的位错,会降低再结晶激活能QR,故在显微组织中发现了亚晶粒,从而降低了合金的强化效果,此时其显微硬度为HV206。该合金在450℃时效处理时组织转变主要有两种：一是第二相弥散分布在铜基体中;另一种是析出与再结晶交互作用而产生的不连续析出。
By analysis of the microhardness and the electrical conductivity and the observation of transmission electron microscOpy （TEM） during aging of Cu-1.4Ni-1.2Co-0.6Si alloy with 30%- 70% cold deformation, it was found that cold deformation could accel- erate the second phase precipitating in early aging stage, and the conductivity increased quickly. After aging at 400 ℃ for 1 h with 30% deformation, the electrical conductivity of the alloy was up to 43% IACS, but with direct aging after solid solution it was 40.7% IACS. After cold rolling-aging, many small precipitates appeared along the dislocation distribution; and dislocation movement was difficult in the aging process, which increased the microhardness in the aging process quickly. The microhardness of the alloy with 30% cold deformation could reach HV223 after aging at 400 ℃ for 2 h; while that of the one with no deformation was HV202. Recrystalliza-tion time ta and aging precipitation time tp depended on deformation and aging system. In a certain shape variables and higher aging temperature conditions, the alloy was prone to generate recrystallized grains. The alloy aging at 500℃ for 2 h after 70% deformation produced high dislocation density in the matrix, which would reduce the activation energy recrystallization Qa. The subgrains was found in the microstructure. Thereby, the strengthening effect of the alloy was reduced, and the hardness of the alloy was HV206. During aging at 450 ℃, there occurred two kinds of main initial phase transformation ： one was preferential precipitation in the region of copper matrix, the other was discontinuous precipitation process produced under the combined effect of precipitation and recrystallization.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2014年第4期596-602,共7页
Chinese Journal of Rare Metals
基金
国家科技部"863"计划项目(2006AA03Z522)
北京市科技计划项目(10231103)资助
