Ti6Al4V合金整体零件的两步热等静压近净成形工艺探究  

Research on Near-Net-Shaping Ti6Al4V Alloy Parts under Two-Step Hot Isostatic Pressing

作　　者：黄俊[1] 薛鹏举[1] 魏青松[1] 史玉升[1] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,武汉430074

出　　处：《中国机械工程》2015年第18期2539-2544,共6页China Mechanical Engineering

基　　金：国家自然科学基金资助项目(51375188);国家科技重大专项(2009ZX04005-041-03)

摘　　要：针对热等静压整体成形高温合金零件容易产生部分区域致密度较低、整体性能不均一的问题,提出了热等静压两步成形方法,在较低的温度和压力作用下成形为不带连通孔隙的原始零件,去除控形模具后用合适的温度压力作用使不致密区域致密,提高零件均一性。以Ti6Al4V粉末材料为例,使用有限元模拟和实验测试相结合的方法,确定了两步成形法的工艺参数,并成形了叶盘零件。SEM结果显示:热等静压两步法成形的零件组织由板条状α+β相组成,原始颗粒边界消失,不连通孔隙闭合。断口形貌显示:在合适的两步成形工艺参数加载下,粉末颗粒冶金结合牢固,不再成为裂纹起始处,拉伸强度提高。两步法拉伸性能略优于常规热等静压拉伸性能,性能达到同规模锻件水平。Monolithic superalloy parts shaped by hot isostatic pressing may exist low density re- gion which will cause uneven overall performance. This paper proposed a two-step hot isostatic press- ing method：at low temperature and pressure original parts were shaped without connected pores from alloy powder,then the low density regions were densed at an appropriate temperature and pressure af- ter removing capsule and shape-control mold, which could guarantee uniform performance. Taking Ti6Al4V powder material as an example,two-step HIP parameters were determined by combining fi- nite element simulation and experimental tests,with which bladed disk parts were made. The SEM re- sults show that.it is fine and homogeneous strip α＋β phase in the parts and there is no prior particle boundary or connected pores, which contribute to the good performance of parts. The fracture mor- phology analysis shows that： the powder particles are metallurgically bonded firmly and no longer the crack source given appropriate processing parameters. Tensile strength of two-step HIP parts is slight- ly better than that of conventional HIP and as same as the forging＇s.

关 键 词：热等静压两步成形 TI6AL4V 有限元模拟 力学性能 

分 类 号：TF124[冶金工程—粉末冶金]