基本信息
项目批准号：51471171
申请代码：E0103
项目名称：钛合金搅拌摩擦焊片层组织的超塑性行为及其在超塑变形中的球化机制
项目负责人：马宗义
依托单位：中国科学院金属研究所
研究期限：2015-01-01 至 2018-12-31
资助经费：84.0（万元）

项目摘要
中文摘要：
超塑成形（SPF）与焊接技术组合用于生产钛合金整体构件具有广阔应用前景，然而熔焊焊核的粗大片层组织不易球化，通常不具有超塑性或超塑性较低，无法实现整体构件的均匀成型。搅拌摩擦焊(FSW)可得到细小片层组织，易于球化，可获得与母材接近的超塑性，因此FSW/SPF成为制备钛合金整体构件的理想选择。然而关于FSW片层组织的超塑变形行为以及微观演变机理尚无公开报导。本项目拟采用FSW对TC4合金进行焊接，得到焊核为片层组织的接头。采用TEM和EBSD技术获得不同FSW参数下片层组织的厚度与长径比及片层取向分布的统计数据；通过拉伸实验获得焊核的超塑性性能；对超塑变形样品进行微观组织分析，获得片层厚度、长径比、取向及相变与球化的关系。通过这些研究，揭示钛合金片层组织球化的微观机制及影响因素，建立从片层组织获得良好超塑性的途径，实现FSW片层组织的可控制备，为钛合金整体构件的FSW/SPF提供参考。
英文摘要：
The combination of superplastic forming (SPF) and welding techniques has great application prospects in producing integrated components of titanium alloys. It is not possible to achieve uniform forming of the integrated components of the fusion welds because the nugget exhibits no or low superplasticity, resulting from the fact that the coarse lamellar microstructure in the nugget is difficult to be spheroidized. Fine lamellar microstructure can be obtained by friction stir welding (FSW) and is easily spheroidized. As a result, the weld nugget can exhibit a comparable superplasticity to the base material. Therefore, FSW/SPF is a sound method to produce integrated components of titanium alloys. However, there is no report on superplastic behavior and microstructure evolution of the lamellar microstructure of FSW titatnium alloy joints during superplastic deformation. In this study, Ti-6Al-4V (TC4) will be welded by FSW, obtaining a lamellar microstructure in the weld nugget. The statistic data of thickness，aspect ratio and misorientation distribution of the lamellae at different FSW parameters will be obtained by TEM and EBSD techniques. The superplastic behavior of the weld nugget will be studied by the tensile test. By microstructural analysis on the deformed specimens, the relationship between thickness, aspect ratio, misorientation, phase transformation, and spheroidization will be built. Through these detailed studies, the mechanism and influential factors of spheroidization of the lamellar microstructure will be clarified. Further, a more effective way to control the lamellar microstructure by controlling FSW parameters and improve their superplasticity will be proposed. All these investigations will provide a guidance for the FSW/SPF process in producing integrated components of titanium alloys.
                                                                                                                                                                         ——来自https://kd.nsfc.gov.cn/