氧化物弥散强化材料的搅拌摩擦焊分析

Friction stir welding of oxide dispersion strengthened material

为了探索搅拌摩擦焊技术应用于氧化物弥散强化材料的可焊接性及其基本特点,文中对厚度为4 mm的氧化物弥散强化铜合金进行了焊接试验,并对焊接接头的宏观形貌、微观组织、显微维氏硬度进行了分析.发现焊接接头横截面由搅拌区、热力影响区、热影响区和母材区4部分组成.前进侧热影响区与热力影响区形成明显的分界线,后退侧则相对模糊.搅拌区的组织为细小的等轴晶粒,出现了洋葱环和L线,热力影响区晶粒沿一定方向发生形变,热影响区组织粗化.沿焊缝横截面的显微维氏硬度呈V形分布,其中搅拌区硬度值最低.

The oxide dispersion strengthened( ODS) copper alloy with 4 mm in thickness was joined by friction stir welding( FSW) to investigate the basic characteristics and feasibility of FSW technology of ODS materials. The microstructure and mechanical properties of ODS-Cu joint were studied. The microstructures of welded joint consist of four parts: weld nugget zone( WNZ),thermo-mechanically affected zone( TMAZ),heat affected zone( HAZ) and base material( BM). The boundary of the TMAZ and HAZ in advanced side is clear,while it is blurred on the retreating side. The WNZ is composed of fine equiaxed recrystallized grains and onion rings structures and 'L'line is observed. Deformed grain is distributed along a certain direction in TMAZ,while the grain coarsens slightly in HAZ. The microhardness along the weld cross-section shows V-shaped distribution and the hardness of WNZ is the lowest.