Microstructure and fracture toughness of Nb-Si based alloys with Ta and W additions

被引：34

作者：

Guo, Yueling ^{[1
]}

Jia, Lina ^{[1
]}

Kong, Bin ^{[1
]}

Zhang, Huarui ^{[1
]}

Zhang, Hu ^{[1
]}

机构：

[1] Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China

来源：

INTERMETALLICS | 2018年 / 92卷

基金：

中国国家自然科学基金;

关键词：

Nb-Si alloy; Silicide; Directional solidification; Fracture toughness; Crack propagation; HIGH-TEMPERATURE STRENGTH; MECHANICAL-PROPERTIES; AS-CAST; ROOM; MO; COMPOSITES; PHASE; CR; HF; DEFORMATION;

D O I：

10.1016/j.intermet.2017.09.005

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The alloying effects of Ta and W on the phase composition, microstructure and room-temperature fracture toughness of Nb-Si based alloys were investigated. The nominal compositions of Nb-Si based alloys were Nb-15Si-24Ti-4Cr-2A1-2Hf (base alloy, at.%), Nb-15Si-24Ti-4Cr-2Al-2Hf-lTa (1Ta alloy, at%) and Nb-15Si-24Ti4-Cr-2A1-2Hf-1W (1W alloy, at.%). Results showed that the base alloy, 1Ta alloy and 1W alloy were composed of Nb solid solution (Nbss), alpha Nb5Si3 and small volumes of hexagonal gamma Nb5Si3 phases. The elements of Ta and W were primarily partitioned in the Nbss phases. The addition of Ta improved the fracture toughness of the base alloy from 10.2 to 12.2 MPa m(1/2), but the addition of W reduced the fracture toughness to 8.2 MPa m(1/2). The fracture of Nbss phases in the three alloys exhibited a cleavage fracture mode, and river patterns were created on individual facets, while the Nb5Si3 phases showed a brittle fracture mode with flat and featureless fracture surfaces. Different with base alloy and 1W alloy, 1Ta alloy involved the occurrence of secondary cracking as well as interface decohesion. The toughening mechanisms of Nb-Si based alloys with Ta and W additions were emphasized.

引用

页码：1 / 6

页数：6

共 40 条

[1] FLOW CHARACTERISTICS OF HIGHLY CONSTRAINED METAL WIRES [J].

ASHBY, MF ;

BLUNT, FJ ;

BANNISTER, M .

ACTA METALLURGICA, 1989, 37 (07) :1847-1857

[2]

ASTM, 2012, ASTM E399-12

[3] The balance of mechanical and environmental properties of a multielement niobium-niobium silicide-based in situ composite [J].

Bewlay, BP ;

Jackson, MR ;

Lipsitt, HA .

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 1996, 27 (12) :3801-3808

[4] A review of very-high-temperature Nb-silicide-based composites [J].

Bewlay, BP ;

Jackson, MR ;

Zhao, JC ;

Subramanian, PR .

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 2003, 34A (10) :2043-2052

[5] Alloying effects on the fracture toughness of Nb-based silicides and Laves phases [J].

Chan, KS .

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 2005, 409 (1-2) :257-269

[6] Improving the fracture toughness of constituent phases and Nb-based in-situ composites by a computational alloy design approach [J].

Chan, KS ;

Davidson, DL .

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 2003, 34A (09) :1833-1849

[7] Alloying effects on fracture mechanisms in Nb-based intermetallic in-situ composites [J].

Chan, KS .

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 2002, 329 :513-522

[8] Effect of Mo on microstructure and mechanical behaviour of as-cast NbSS-Nb5Si3 in situ composites [J].

Chattopadhyay, K. ;

Balachandran, G. ;

Mitra, R. ;

Ray, K. K. .

INTERMETALLICS, 2006, 14 (12) :1452-1460

[9] Microstructure evolution and room temperature deformation of a unidirectionally solidified Nb-22Ti-16Si-3Ta-2Hf-7Cr-3Al-0.2Ho (at.%) alloy [J].

Cheng, G. M. ;

He, L. L. .

INTERMETALLICS, 2011, 19 (02) :196-201

[10] The deformation and fracture modes of fine and coarsened Nbss phase in a Nb-20Si-24Ti-2Al-2Cr alloy with a Nbss/Nb5Si3 microstructure [J].

Fei, Teng ;

Yu, Youxing ;

Zhou, Chungen ;

Sha, Jiangbo .

MATERIALS & DESIGN, 2017, 116 :92-98

← 1 2 3 4 →