基于正交试验设计的QBe2铍青铜热处理工艺优化

Optimization of Heat Treatment Process for QBe2 Beryllium Bronze Based on Orthogonal Experimental Design

  • 摘要: 采用L₉(3³)正交试验设计优化QBe2铍青铜合金的热处理工艺参数,研究固溶温度(780、800、820℃)、时效温度(300、325、350℃)和时效时间(1、2、3h)对硬度和显微组织的影响。结果表明:时效温度对硬度影响最显著,固溶温度次之,时效时间影响较小。方差分析显示,时效温度和固溶温度对硬度影响极显著,时效时间影响显著。最优工艺参数为固溶800℃×10min+时效325℃×3h,合金维氏硬度达到385±6HV0.1。显微组织分析表明,合金由α-Cu基体、少量残余β相、晶内弥散γ′析出相和晶界不连续析出相组成。在325℃时效时,γ′相尺寸为纳米级且分布均匀,沉淀强化效果最佳;350℃时发生过时效,析出相粗化并出现不连续析出,导致硬度下降。合金的强化机制包括Orowan绕过机制、共格应变强化和溶质强化。

     

    Abstract: The heat treatment process parameters of QBe2 beryllium bronze alloy were systematically optimized using L₉(3³) orthogonal experimental design. Under the condition of solution treatment time of 10 min, the effects of solution temperature (780, 800, 820℃), aging temperature (300, 325, 350℃), and aging time (1, 2, 3 h) on the hardness and microstructure of the alloy were investigated. The results show that aging temperature has the most significant effect on alloy hardness (range R=28.7), followed by solution temperature (R=27.0), and aging time has a relatively small effect (R=14.3). Analysis of variance reveals that aging temperature and solution temperature have a highly significant effect on hardness (P < 0.01), while aging time has a significant effect (P < 0.05). The optimal process parameters are solution treatment at 800℃ for 10 min + aging at 325℃ for 3 h, and the Vickers hardness of the alloy reaches 385±6 HV0.1. Microstructural analysis reveals that the alloy consists of an α-Cu matrix, a small amount of residual β phase, intragranular γ′ precipitates, and grain boundary discontinuous precipitates. At 325℃ aging, the size of the γ 'phase is nanoscale and evenly distributed, achieving the best precipitation strengthening effect. At 350℃, over-aging occurs, characterized by precipitate coarsening and discontinuous precipitation, leading to a reduction in hardness. The strengthening mechanisms mainly include the Orowan looping mechanism, coherency strain strengthening, and solute strengthening, with multiple mechanisms working synergistically to achieve high strength.

     

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