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在进料速率0.5 mm/s,冷热源距离15 mn保持不变,拉拔速率0.8—1.1 mm/s,变形温度650—900℃的条件下,对连续柱状晶组织Cu-14.0%Al-3.8%Ni(质量分数)合金线材进行了无模拉拔实验,研究了无模拉拔工艺与合金显微组织和力学性能的关系,并对变形后合金组织性能演变的机理进行了探讨.结果表明:平直晶界连续柱状晶合金线材经无模拉拔变形后,可形成平直晶界和锯齿状晶界连续柱状晶、不完全动态再结晶和完全动态再结晶4种微观组织.在变形温度650℃,拉拔速率0.80.9 mm/s的范围内,变形后合金仍然保持平直晶界连续柱状晶组织;随着变形温度和拉拔速率的提高,连续柱状晶的平直晶界向锯齿状晶界转变.当拉拔速率为0.9 mm/s,变形温度上升至850℃时,合金呈现出明显的不完全动态再结晶的组织特征,即原始柱状晶粒沿变形方向拉长变细,在部分锯齿状晶界处有细小的动态再结晶晶粒产生;继续升高温度至900℃,合金发生完全动态再结晶,大量等轴、尺寸较大的动态再结晶晶粒完全取代了变形的柱状晶粒.拉拔变形后合金线材的抗拉强度随着变形温度的升高先小幅度增加然后显著降低,而伸长率则单调降低.
Under the conditions of feed rate of 0.5 mm / s, distance between cold and heat source of 15 mn, drawing speed of 0.8-1.1 mm / s and deformation temperature of 650-900 ℃, the continuous columnar crystal structure of Cu-14.0% Al- 3.8% Ni (mass fraction) alloy wire was drawn by the die-free drawing method, the relationship between the die-less drawing process and the microstructure and mechanical properties of the alloy was studied, and the mechanism of the microstructure evolution was discussed. The results show that there are four kinds of microstructures in the continuous grain-oriented straight-line grain-oriented straight-wire alloys, such as flat columnar grain boundary, zigzag grain boundary continuous columnar grain, incomplete dynamic recrystallization and complete dynamic recrystallization. The deformation temperature is 650 ℃ and the drawing rate is 0.80.9 mm / s, the alloy still maintains the continuous columnar grain structure in the flat grain boundary after deformation. With the increase of deformation temperature and drawing rate, The grain boundary changes to jagged grain boundary.When the drawing rate is 0.9 mm / s and the deformation temperature rises to 850 ℃, the microstructure of the alloy shows obvious dynamic recrystallization, that is, the original columnar grain elongated along the deformation direction Narrow, in some jagged grain boundaries have small dynamic recrystallization grains , And the dynamic recrystallization of the alloy occurred completely with increasing temperature up to 900 ℃, a large number of dynamic recrystallization grains with isometric size and larger size completely replaced the deformed columnar grains.The tensile strength of the alloy wire after drawing deformation The deformation temperature increases slightly and then decreases significantly, while the elongation decreases monotonically.