摘要
借助超音速微粒轰击(SFPB)对片层组织的Ti−6.5Al−3.5Mo−1.5Zr−0.3Si(TC11)钛合金进行表面纳米化处理,并系统研究SFPB气体压力对其表面完整性、显微组织演变和力学性能的影响规律。结果表明,在不同SFPB气体压力下,TC11钛合金表层均已形成梯度纳米结构。表层片层组织晶粒尺寸完全碎化至纳米量级,且纳米晶晶粒尺寸随着气体压力的增大而减小,而次表层组织仍保留原始片层形貌。经1.0 MPa处理后,表面粗糙度最小,在1.5 MPa时表面形成微裂纹,表层残余压应力下降。随着SFPB气体压力的增大,表层显微硬度及硬化层深度逐渐增加,屈服强度、抗拉强度增加,而伸长率变化不大,断口形貌从典型的韧性断裂向准解理和韧性混合型断裂转变。
The surface nanocrystallization of a Ti−6.5Al−3.5Mo−1.5Zr−0.3Si(TC11)titanium alloy with a lamellar microstructure was carried out by supersonic fine particle bombardment(SFPB).The effect of SFPB gas pressure on its surface integrity,microstructural evolution and mechanical properties was systematically investigated.The results showed that gradient nanostructures on the surface of the TC11 alloy were successfully created after SFPB with different gas pressures.The grain size of the surface’s lamellar microstructure was completely refined to the nanometer scale.And the grain size of nanocrystals decreased with the increase of gas pressure.Meanwhile,the subsurface retained initial lamellar microstructure morphology.Surface roughness was minimized after SFPB with a gas pressure of 1.0 MPa,while microcrack formed at a higher gas pressure of 1.5 MPa,resulting in a decrease of compressive residual stress.With the increase of SFPB gas pressure,the surface microhardness and the depth of hardened layer gradually increased,and yield strength and tensile strength was improved.Nevertheless,the elongation was not greatly changed.The fracture morphology changed from typical ductile fracture to quasi-cleavage and ductile mixed fracture.
作者
武永丽
熊毅
陈正阁
刘伟
张鑫
王树泊
曹伟
Yong-li WU;Yi XIONG;Zheng-ge CHEN;Wei LIU;Xin ZHANG;Shu-bo WANG;Wei CAO(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023,China;Provincial and Ministerial Co-construction Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology,Luoyang 471023,China;State Key Laboratory of Laser Interaction with Matter,Northwest Institute of Nuclear Technology,Xi’an 710024,China;Nano and Molecular Systems Research Unit,University of Oulu,FIN-90014,Finland)
基金
supported by the National Natural Science Foundation of China(Nos.U1804146,51801054,52111530068)
the Program for Science and Technology Innovation Talents in Universities of Henan Province,China(No.17HASTIT026)
the Foreign Experts Introduction Project of Henan Province,China(No.HNGD2020009)
the Science and Technology Innovation Team of Henan University of Science and Technology,China(No.2015XTD006)
the Academy of Finland(No.311934)。
关键词
超音速微粒轰击
气体压力
钛合金
片层组织
表面纳米化
显微组织
力学性能
supersonic fine particle bombardment
gas pressure
titanium alloy
lamellar microstructure
surface nanocrystallization
microstructure
mechanical properties
