Shin Hye-Jeong, Kim Min-Jung, Kim Hyung-Il, Kwon Yong Hoon, Seol Hyo-Joung
Department of Dental Materials, Institute of Translational Dental Science and BK21 PLUS Project, School of Dentistry, Pusan National University.
Dent Mater J. 2017 Mar 31;36(2):142-148. doi: 10.4012/dmj.2016-279. Epub 2017 Jan 13.
This study examined the effect of ice-quenching after degassing on the change in hardness of a Pd-Au-Zn alloy during porcelain firing simulations. By ice-quenching after degassing, the specimens were softened due to homogenization without the need for an additional softening heat treatment. The lowered hardness by ice-quenching after degassing was recovered greatly from the first stage of porcelain firing process by controlling the cooling rate. The increase in hardness during cooling after porcelain firing was attributed to the precipitation of the f.c.t. PdZn phase containing Au, which caused severe lattice strain in the interphase boundary between the precipitates and matrix of the f.c.c. structure. The final hardness was slightly higher in the ice-quenched specimen than in the specimen cooled at stage 0 (the most effective cooling rate for alloy hardening) after degassing. This was attributed to the more active grain interior precipitation during cooling in the ice-quenched specimen after degassing.
本研究考察了脱气后冰淬对烤瓷模拟过程中钯 - 金 - 锌合金硬度变化的影响。通过脱气后进行冰淬，试样因均匀化而软化，无需额外的软化热处理。脱气后冰淬导致的硬度降低在烤瓷过程的第一阶段通过控制冷却速率得以大幅恢复。烤瓷后冷却过程中硬度的增加归因于含金的面心四方 PdZn 相的析出，这在面心立方结构的析出物与基体的相间边界处引起了严重的晶格应变。脱气后冰淬试样的最终硬度略高于脱气后在阶段 0（合金硬化的最有效冷却速率）冷却的试样。这归因于脱气后冰淬试样在冷却过程中晶粒内部析出更为活跃。
