均匀化热处理参数对7085铸锭组织性能的影响

Effects of Homogenizing Heat Treatment Parameters on Microstructure and Properties of 7085 Ingot

以7085大规格半连续铸锭为研究对象,对其进行了不同的均匀化热处理,研究了热处理温度与时间对7085铸锭组织与性能的影响,对比分析了单级与双级均匀化热处理后的材料性能。结果表明,7085大规格铸锭升温速率约为0.4℃/(min·mm)时,铸态枝晶组织与晶界区域低熔点T相经均匀化热处理后基本溶入初生α-Al基体内部,材料塑性与电导率得到明显改善。经(430±5)℃×8 h+(460±5)℃×24 h热处理后材料的平均抗拉强度、屈服强度、伸长率与电导率分别为352 MPa、264 MPa、13.3%与19.616 MS/m,断口表面以沿晶断裂为主。

Effects of homogenizing heat treatment temperature and time on microstructure and properties of 7085 large semi-continuous ingot were investigated and compared with the different process systems. The results indicate that when the temperature-increment rate is about 0.4 ℃/(min·mm), the low-melting T phase and as-cast dendrite structure are melted into the primary α-Al matrix after the homogenizing heat treatment process, leading to the obvious improvement of plasticity and electrical conductivity. The average tensile strength, yield strength, elongation and conductivity reach 352 MPa, 264 MPa, 13.3% and 19.616 MS/m, respectively, after heat treatment for(430±5) ℃×8 h+(460±5) ℃×24 h, where the facture surface is dominated by intercrystalline fracture.