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| 快速凝固条件下Ni–Pb偏晶合金的组织演变机理研究 |
| Continuous Microstructure Evolution of Ni-Pb Monotectic Alloy under Rapid Solidification |
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| DOI：10.3969/j.issn.1674-6457.2022.06.020 |
| 中文关键词: Ni–Pb合金 过冷组织演化 深过冷 晶粒细化 应力积累 |
| 英文关键词: Ni-Pb alloy subcooled microstructure evolution deep undercooling grain refinement stress accumulation |
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| 中文摘要: |
| 目的 研究过冷Ni–0.5%Pb(原子数分数)合金过冷组织的演化行为，阐明其组织演化和晶粒细化的基本机制。方法 采用熔融玻璃净化和循环过热方法制备出过冷度为0~255 K的试样，并结合枝晶生长的动力学–热力学模型，研究其深过冷快速凝固行为机制。结果 在0~255 K过冷度范围内，随着过冷度的增大，Ni–Pb偏晶合金的微观组织发生了2类晶粒细化现象，组织形态由粗大树枝晶向粒状等轴晶转变。结论 第1类粒状晶的形成是由于枝晶熟化和再辉重熔导致发达枝晶破碎，第2类粒状晶的形成是由于在应力和应变能的作用下，枝晶碎变和再结晶引起了晶粒细化。 |
| 英文摘要: |
| This paper aims to study the subcooled microstructure evolution behavior of supercooled Ni–0.5%Pb (atomic fraction) alloys, and to clarify the basic mechanism of microstructure evolution and grain refinement. The samples with subcooling degree of 0-255 K were prepared by the method of molten glass purification and cyclic superheating, and combined with the kinetic-thermodynamic model of dendrite growth, the mechanism of rapid solidification behavior in deep subcooling was studied.In the range of 0-255 K undercooling, with the increase of undercooling, two types of grain refinement occurred in the microstructure of Ni-Pb monotectic alloy, and the microstructure changed from coarse dendrite to granular equiaxed. crystal transformation. The formation of the first type of granular crystals is due to the fragmentation of developed dendrites caused by dendrite maturation and re-melting. The formation of the second type of granular crystals is due to dendrite fragmentation and recrystallization under the action of stress and strain energy. |
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