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本文研究了铍青铜(QBe2)不连续析出组织形貌、形成条件、生长规律及其与时效工艺的关系。试验证明:软态合金于300～500℃,硬态合金于350～500℃时效,晶界处产生明显的不连续析出,胞状组织内部除了片状析出相之外,尚存在点状、棒状及纤维状析出。采用150～210℃低温时效后再进行正常时效,可以抑制不连续析出的产生。理论分析结果表明:在 QBe2合金中不连续析出的产生与固溶体内的铍浓度有关,且提出一个新的形核设想——晶界偏析与界面迁移形成不连续析出。利用 Sundguist 长大理论考察 QBe2合金不连续析出长大,肯定了胞长大的晶界扩散机制。
In this paper, the morphology, formation conditions, growth rules and the relationship with the aging process of discontinuous precipitation of beryllium bronze (QBe2) were studied. The experimental results show that the hard alloy at 300-500 ℃ and the hard alloy at 350-500 ℃ have obvious discontinuous precipitation at the grain boundaries. In addition to the platelet-like precipitates, the intragranular structure exists in the form of punctate, Fibrous precipitation. Using 150 ~ 210 ℃ low temperature aging and then the normal aging, can inhibit the generation of discontinuous precipitation. The theoretical analysis shows that the discontinuous precipitation in QBe2 alloy is related to the concentration of beryllium in solid solution, and a new nucleation assumption - grain boundary segregation and interfacial migration is proposed to form discontinuous precipitation. Using Sundguist growth theory to investigate the discontinuous growth and precipitation of QBe2 alloy, affirmed the cell growth of the grain boundary diffusion mechanism.