【摘要】 通过显微组织观察和性能测试,研究了固溶处理对石膏型铸造Al-Cu-Ti合金显微组织及力学性能的影响。结果表明,由于石膏型铸态晶粒粗大,改变固溶温度不仅影响沉淀相结构和分布,而且也使固溶体中的空位浓度和合金元素浓度发生变化,从而直接影响时效过程中固溶体的脱溶次序。固溶温度过高或过低,在固溶处理的加热或冷却过程中,均能明显激活枝晶边缘的形核位置,使得时效过程中沉淀相平均尺寸相对增大。固溶温度为530℃时力学性能和显微组织最好,这主要归因于固溶体按GP区过渡相(θ″和θ′)方式脱溶,而θ相粗化明显使强度下降。更多还原

【Abstract】 Effects of the solution treatment on the microstructure and mechanical properties of Al-Cu-Ti alloy of gypsum mold casting were investigated by means of microstructure observations and tensile tests, the results show that because of coarse as-cast grains by gypsum mold casting, the change of the solution temperature not only affected the structure and the distribution of the precipitates, but also changed the vacancy concentrations and the solute concentration, which had a direct influence on the precipitation sequence of precipitate during aging. With too high or too low of solution temperature, the nucleation sites could significantly be activated on the dendrite edge during the quenching or the heating for solution treatment, which could make relatively large size of precipitates form in the aging process. Optimal solution temperature with maximum mechanical properties and best microstructure is 530 ℃, which can be attributed to the formation of the GP zones and transition phase( θ′′, θ′) as fine particles within the matrix in the aging process, the mechanical properties decrease with θ phase coarsening.更多还原