Simultaneous enhancements of strength and toughness by multiscale lamellar structure in Ti_(2)AlNb based intermetallic  

作　　者：Fan Zhang Weidong Zeng Penghui Zhang Haoyuan Ma Jianwei Xu 

机构地区：[1]State Key Laboratory of Solidification Processing,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China [2]Defense Technologies Innovation Center of precision forging and ring rolling,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China

出　　处：《Journal of Materials Science & Technology》2024年第7期249-261,共13页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52275380).

摘　　要：Multi-scale lamellar structure significantly improves toughness of Ti_(2)AlNb based alloys,which are inher-ently brittle intermetallics,without compromising their strength.This structure was achieved through-B2-transus-forging(TBTF)combined with O+B2 two-phase region heat treatments.Various types of multi-scale lamellar structures were obtained by controlling the cooling rate after TBTF.These variations were mainly attributed to differences in the distribution,content,and size of the thick lamellar O phase and the size and crystallographic orientation of B2 grain.By analyzing the microstructural characteristics and crystallographic orientation near the crack propagation path,it was found that the crack propaga-tion resistance of thick lamellae,sub grain and grain boundaries(GBs)O phase increased sequentially,accompanied by more tortuous crack propagation path.Moreover,B2 grains with high misorientation significantly deflected the crack propagation by cleavage ridges between adjoining cleavage planes.Addi-tionally,the development of numerous secondary cleavage ridges,resulting from the transition through varying secondary cleavage planes in distinct sub B2 grains,further hindered the quick propagation of cracks.It was clarified that the cleavage planes were dominantly belonging to{110}.These findings pro-vided valuable guidance for the design of damage tolerance strategies for Ti_(2)AlNb-based intermetallics.

关 键 词：Multiscale lamellae structure Fracture toughness Crack propagation Ti_(2)AlNb-based intermetallic Through-B2-transus-forging 

分 类 号：TQ317[化学工程—高聚物工业] TB33[一般工业技术—材料科学与工程]