固溶时效对Ti6242合金组织性能的影响

Effect of Solution and Aging on Microstructure and Tensile Properties of Ti6242 Alloy

对轧制态Ti6242合金棒材进行固溶时效热处理,分析了固溶温度对材料组织与性能的影响;并通过图像处理得到了不同固溶温度下的组织参数,对组织与性能的关系作定量分析。结果表明,相变点（差热法测得相变点为991℃）以下,固溶温度在910～985℃时的抗拉强度和屈服强度随温度的升高呈下降趋势,塑性变化较小;随固溶温度的升高,等轴α尺寸及片层厚度的增加,克服了条状α增加对强度的贡献作用,导致抗拉强度及屈服强度降低,对塑性影响较小。在相变点之上,在1000～1030℃固溶时,抗拉强度和屈服强度变化较小,而塑性迅速下降;这是因为1000℃固溶时,等轴α含量降低显著（5%～6%）,组织的变形协调能力下降,塑性降低,条状α尺寸的增加引起了抗拉强度和屈服强度降低,1015～1030℃固溶时,其显微组织为魏氏体,表现为强度和塑性的急剧减小,1030℃固溶时片层α的长度减小,宽度增大,材料性能有所回升。

Solution and aging treatment of Ti6242 alloy was carried out, and the effects of solution temperature on microstructure and properties were analyzed. The results show that, under the phase transformation point（measured by differential thermal phase transition point of 991℃）, the solution temperature below 910℃- 985℃, the tensile strength and yield strength decrease with the increase of solution temperature, and plasticity changes little; as the size of equiaxed αincreases and sheet thickness causes, the tensile strength and yield strength are reduced. Above the phase transition point, at the solution temperature 1000 ℃-1030 ℃, the tensile strength and yield strength change little, and ductility rapidly decreases.This is because at the solution temperature 1000℃, the equiaxed α levels are significantly lower, about 5% to 6% decline in the ability to organize coordinated deformation plasticity reduces, the size of the strip α increasing, causes a lower tensile strength and yield strength. When the solution temperature is 1015℃-1030℃, the microstructure is Widmannstatten structure, and the strength and ductility decreases sharply. While the length of lamellar α decreases at 1030 ℃, the width increases, the material properties reboundes.