摘要
利用碳复型萃取技术和先进测试方法对我国生产的FGH96合金中形成的原始粉末颗粒边界(previous particle boundaries,PPB)进行研究.结果表明,PPB的实质是析出相沿原始粉末颗粒边界连续或半连续分布而呈现出的组织形貌.PPB析出相组成受热等静压(HIP)温度影响,当高于γ′相固溶温度,HIP得到的PPB析出相主要为MC(M主要为Ti,Nb和Zr)型碳化物,低于固溶温度时则为MC和γ′相.PPB析出相形成于高温高压固化成型过程中,粉末表面层固溶体中偏析的C和Ti等溶质元素与粉末表面上吸附的O发生化学反应形成PPB析出相,而粉末表面MC型碳化物及γ′相形成元素的富集促进了这一反应的进行.PPB的形成是由粉末表面固有原子结构与合金元素偏析等特性决定的,难以彻底消除,只能选择合适的粉末尺寸和控制致密化成型工艺参数来使PPB最小化.
The previous particle boundaries （PPB） introduced in the PM （powder metallurgy） superalloys during their fabrication process are deleterious to the mechanical properties of the super- alloys. The elimination and the minimization of the PPB are the keys to promote the metallurgical quality of the PM superalloys. The carbon replica methods and advanced analytic techniques were utilized to study the PPB formed in FGH96 alloy. The result shows that the multi element carbides and large γ＇ phase decorate the outline of the PPB. The PPB precipitates in the alloy which is hot isostatic pressed （HIPed） below the solution temperature of the γ＇ phase are mainly γ＇ phase and MC （the metalic elements are mainly Ti, Nb and Zr）, while those in the alloy HIPed above the temperature are MC. The supersaterated solutes on the powder surface react with the carbon and oxygen of the surface during the HIP process, which leads to the formation of the PPB precipitates. Besides, the segregation of the MC and γ＇ phase forming elements speed up the reaction above. The characteristics and the elements segregation of the initial powder surface inevitably lead to the formation of PPB and, as a result, the PPB can not be completely eliminated. Selecting proper size range of the initial powders for HIP and strict controls of the HIP parameters are the kev key tominimizing the PPB.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第10期1248-1254,共7页
Acta Metallurgica Sinica
基金
国家重点基础研究发展计划项目2010CB631204
国家自然科学基金项目51071019资助~~
