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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。
Through the analysis of the microhardness and conductivity of the Cu-1.4Ni-1.2Co-0.6Si alloy with cold deformation of 30% -70% and the transmission electron microscope observation, it is found that the cold deformation of the solution alloy can be The second phase accelerated precipitation aging precipitation, the conductivity increased rapidly. If the alloy after 30% deformation 400 ℃ aging 1 h after the conductivity up to 43% IACS, and the direct solution after solution aging 40.7% IACS. After the cold-aging, many fine precipitates are distributed along the dislocations to make the dislocation difficult to move during the aging process. At the same time, high-density dislocations are formed in the alloy, and the precipitates are dispersed and distributed in the matrix in small size. Therefore, Get higher microhardness, such as 30% deformation at 400 ℃ aging 2h its microhardness up to HV223, without the deformation of the direct aging alloy microhardness HV202. During the process of precipitation and recrystallization, the recrystallization time (tR) and aging precipitation time (tP) depend on the amount of deformation and the aging regime. Under a certain amount of deformation and high aging temperature, recrystallization of recrystallization occurs in the alloy. 70% deformation of the alloy at 500 ℃ aging 2 h, due to the high density of dislocations generated in the matrix will reduce the recrystallization activation energy QR, so found in the microstructure subgrains, thereby reducing the strengthening effect of the alloy, this time Its microhardness HV206. There are mainly two kinds of microstructural transformation during the aging treatment at 450 ℃: one is the second phase dispersed in the copper matrix; the other is the discontinuous precipitation caused by the interaction between precipitation and recrystallization.