工程科学学报2016，Vol.38Issue(3)：379-384,6.DOI:10.13374/j.issn2095-9389.2016.03.012
高铌TiAl合金的高温断裂韧性
High-temperature fracture toughness of high Nb-containing TiAl alloys
摘要
Abstract
The fracture toughness of a nearly lamellar Ti-45Al-8Nb-0. 2W-0. 2B-0. 1Y alloy and a fully lamellar Ti-45Al-7Nb-0. 2W-0. 2Hf-0. 3B-0. 15C alloy at 750℃ was investigated by prefabricating a fatigue crack in the compact tension (CT) speci-men, and the corresponding fracture morphologies were observed by optical microscopy and scanning electron microscopy. It is found that the fracture toughness of the nearly lamellar high Nb-containing TiAl alloy is 19. 54 MPa·m1/2 at 750℃, obviously lower than the value of 31. 58 MPa·m1/2 for the fully lamellar alloy. The maximum cyclic load at which the fatigue crack initiates in the nearly lamellar alloy is noticeably less than that in the fully lamellar alloy. Fracture images show that for the nearly lamellar alloy, cracks initiate mainly in equiaxedγgrains and propagate in different ways, intergranularly or transgranularly inγgrains or lamellar colonies. But for the fully lamellar alloy, cracks initiate mainly at lamellar interfaces perpendicular to the load direction and propagate in both interla-mellar and translamellar ways, in accompanying with secondary crack initiation.关键词
钛铝合金/断裂韧性/高温性能/疲劳裂纹/裂纹萌生/裂纹扩展Key words
titanium aluminum alloys/fracture toughness/high temperature properties/fatigue cracks/crack initiation/crack propagation分类
矿业与冶金引用本文复制引用
余龙,宋西平,张敏,焦泽辉,于慧臣..高铌TiAl合金的高温断裂韧性[J].工程科学学报,2016,38(3):379-384,6.基金项目
国家重点基础研究发展计划资助项目(2011CB605506) （2011CB605506）
