摘要
针对BT20钛合金锻件当量孔损伤进行激光沉积修复试验,考察了修复试样的组织和力学特点.修复区与基材之间形成了致密冶金结合,Al,Zr,Mo,V合金元素由锻件基体到激光修复区均匀分布,无宏观偏析,硬度分布从基材到修复区依次提高.热影响区组织是由基材的双态组织过渡到网篮组织;修复区组织为粗大的原始柱状β晶,晶粒内为α/β网篮组织,晶内α片层取向随机,宽0.4～0.5 μm.修复过程中发现,激光加工工艺参数选择不当、坡度过大等原因会造成修复区组织形成气孔和熔合不良等缺陷,但是通过优化工艺参数可以获得无缺陷修复试样.修复试样的室温静拉伸结果表明,试样的抗拉强度接近锻件基体强度,但修复件的韧性比锻件稍有提高.
Researches on the laser deposition repair of BT20 alloy forgings having hole damage were carried out, and the microstructure characteristic of laser deposition repair component was analyzed. There was a dense metallurgical bond between the repaired zone and the substrate. The Al, Zr, Mo, V elements were uniformly distributed without fluctuation and segregation from the matrix to the laser repaired zone. The repaired component experienced a continuous microstructural transition from duplex microstructure with equiaxed α and lamellar α/β in the repaired substrate to the epitaxial coarser columnar β with basket weave α/β through heat-affected zone. In the heat affected zone, the microstructure changed from bimodal structure to the basket weave structure gradually, and the repaired zone was characterized by a fine α/β lamellar microstructure with various random orientations, and the α was about 0.4-0.5 um, which should be related to the rapid solidification and phase transformation during the process. It is found that unsuitable laser process parameters and large hole sloped angle can cause defects such as gas porosities and ill bonding. The results of repaired sample tensile test at room temperature show that the tensile strength approaches to the wrought BT20 alloy, while its toughness is a little higher.
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2014年第2期294-298,共5页
High Power Laser and Particle Beams
基金
国家自然科学基金项目(51305280
51375316)
辽宁省教育厅科学技术研究项目(L2013077)
国防基础科研项目(A3520133001)
中航工业产学研创新工程(CXY2011SH16)
关键词
激光沉积成形
激光沉积修复
BT20钛合金
显微组织
力学性能
显微硬度
laser metal deposition
laser deposition repair
BT20 titanium alloy
microstructure
mechanical properties
microhardness
