Superlattice dislocations in Ti-rich polysynthetically twinned crystals of TiAl

IMR OpenIR

	Superlattice dislocations in Ti-rich polysynthetically twinned crystals of TiAl
	Y. Liu; D. L. Lin; Z. G. Liu; Z. G. Wang
	1999
发表期刊	Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties
ISSN	0141-8610
卷号	79 期号:12 页码:2965-2978
摘要	The behaviour of superlattice dislocations in polysynthetically twinned (PST) TiAl crystals deformed from room temperature to 850 degrees C is studied by transmission electron microscopy. The dissociation modes undergo significant changes with increasing deformation temperature. At room temperature, the [011] superlattice dislocations dissociate into superpartials including either an antiphase boundary and a superlattice intrinsic stacking fault (SISF), or superlattice extrinsic stacking faults (SESFs), forming faulted dipoles, and are sessile. The 1/2[112] superlattice dislocations dissociate into faulted dipoles and are also sessile. While the dislocation configurations in the crystals deformed at 400 degrees C and 600 degrees C are identical with those in the crystals deformed at room temperature, one important variation is that the density of faulted dipoles decreases with increasing deformation temperature. In-situ heating observations show that self-annihilation of the SESF-bounding hairpin superpartial occurs within a temperature range that compares with that of the brittle-ductile transition of PST TiAl crystals. At 850 degrees C, most [011] superlattice dislocations dissociate to form Kear-Wilsdorf locks. The 1/2[112] superlattice dislocations are edge in character, dissociated into superpartials bordering a SISF and are glissile. The experimental observations suggest that the behaviour of 1/2[112] superlattice dislocations is an important factor controlling the mechanism of brittle-ductile transition of PST TiAl crystals.
部门归属	shanghai jiao tong univ, sch mat sci & engn, open lab educ, ministry china high temp mat & tests, shanghai 200030, peoples r china. nanjing univ, natl key lab solid state microstructures, nanjing 210093, peoples r china. chinese acad sci, state key lab fatigue & fracture mat, inst met res, shenyang 110015, peoples r china.;liu, y (reprint author), shanghai jiao tong univ, sch mat sci & engn, open lab educ, ministry china high temp mat & tests, shanghai 200030, peoples r china, peoples r china
关键词	Room-temperature Deformation Mechanisms Yield Stress Lamellar Structure Single-crystals Faulted Dipoles Pst Crystals Base Alloys Al Dependence
URL	查看原文
WOS记录号	WOS:000084280500007
引用统计	被引频次：2[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/37431
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Y. Liu,D. L. Lin,Z. G. Liu,et al. Superlattice dislocations in Ti-rich polysynthetically twinned crystals of TiAl[J]. Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties,1999,79(12):2965-2978.
APA	Y. Liu,D. L. Lin,Z. G. Liu,&Z. G. Wang.(1999).Superlattice dislocations in Ti-rich polysynthetically twinned crystals of TiAl.Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties,79(12),2965-2978.
MLA	Y. Liu,et al."Superlattice dislocations in Ti-rich polysynthetically twinned crystals of TiAl".Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties 79.12(1999):2965-2978.