Superplasticity in Metals And Ceramics

by T. G. Nieh , J. Wadsworth , O. D. Sherby

• ISBN13: 9780521020343
• ISBN10: 0521020344
• Format: Paperback
• Copyright: 2005-09-29
• Publisher: Cambridge University Press

Summary

This book describes advances in the field of superplasticity. This is the ability of certain materials to undergo very large tensile strains, a phenomenon that has increasing commercial applications, but also presents a fascinating scientific challenge in attempts to understand the physical mechanisms that underpin it. The authors emphasise the materials aspects of superplasticity. They begin with a brief history of the phenomenon. This is followed by a description of the two major types of superplasticity ' fine-structure and internal-stress superplasticity ' together with a discussion of their operative mechanisms. In addition, microstructural factors controlling the ductility and fracture in superplastic materials are presented. The observations of superplasticity in metals (including aluminium, magnesium, iron, titanium and nickel), ceramics (including monoliths and composites), intermetallics (including iron, nickel, and titanium base), and laminates are thoroughly described. The technological and commercial applications of superplastic forming and diffusion bonding are presented and examples given.

Table of Contents

Preface	xiii
Chapter 1 Introduction	1	(2)
References	3	(2)
Chapter 2 Bey historical contributions	5	(17)
2.1 Before 1962	5	(4)
2.2 From 1962 to 1982	9	(1)
2.3 From 1982 to the present	9	(8)
References	17	(5)
Chapter 3 Types of superplasticity	22	(10)
3.1 Fine-structure superplasticity (FSS)	22	(6)
3.1.1 Fine grain size	23	(1)
3.1.2 Second phases	24	(1)
3.1.2.1 Strength of the second phase particle	24	(1)
3.1.2.2 Size, morphology, and distribution of the second phase	24	(1)
3.1.3 Nature of grain-boundary structure	25	(2)
3.1.3.1 Grain-boundary orientation	25	(1)
3.1.3.2 Homophase and heterophase	26	(1)
3.1.4 Texture and shape of grains	27	(1)
3.1.5 Mobility of grain boundaries	28	(1)
3.1.6 Grain boundaries and their resistance to tensile separation	28	(1)
3.2 Internal-stress superplasticity (ISS)	28	(1)
3.3 High-strain-rate-superplasticity (HSRS)	29	(1)
Other mechanisms	29	(1)
References	30	(2)
Chapter 4 Mechanisms of high-temperature deformation and phenomenologcal relations for fine-structure superplasticity	32	(26)
4.1 Creep mechanisms	32	(8)
4.1.1 Diffusional creep (n=1)	34	(2)
4.1.1.1 Nabarro–Herring creep	34	(1)
4.1.1.2 Coble creep	34	(2)
4.1.2 Grain-boundary sliding (n=2)	36	(1)
4.1.3 Dislocation creep	36	(2)
4.1.3.1 Glide-controlled creep (n=3)	37	(1)
4.1.3.2 Climb-controlled creep (n=4-5)	37	(1)
4.1.4 Dispersion-strengthened alloys (n>8)	38	(2)
4.2 Grain-boundary sliding with various accommodation processes	40	(9)
4.3 Optimizing the rate of superplastic flow in FSS materials	49	(5)
References	54	(4)
Chapter 5 Fine-structure superplastic metals	58	(33)
5.1 Aluminum-based alloys	58	(11)
5.1.1 Academic studies 6o
5.1.2 Alloys designed for room-temperature properties as well as superplasticity	63	(1)
5.1.3 Commercial alloys	64	(5)
5.2 Magnesium-based alloys	69	(4)
5.3 Iron-based alloys	73	(6)
5.3.1 Plain carbon steels	73	(3)
5.3.1.1 Hypoeutectoid and eutectoid steels	73	(1)
5.3.1.2 Hypereutectoid steels	74	(2)
5.3.1.3 White cast irons	76	(1)
5.3.2 Low- and medium-alloy-content steels	76	(1)
5.3.2.1 Ferrite and austenite	77	(1)
5.3.2.2 Austenite	77	(1)
5.3.3 Microduplex stainless steels	77	(2)
5.3.4 Nonsuperplastic steels made superplastic by lamination	79	(1)
5.4 Titanium-based alloys	79	(4)
5.5 Nickel-based alloys	83	(2)
References	85	(6)
Chapter 6 Fine-structure superplastic ceramics	91	(34)
6.1 Monolithic ceramics	93	(8)
6.1.1 Yttria-stabilized tetragonal zirconia polycrystal	93	(6)
6.1.1.1 Microstructure	93	(2)
6.1.1.2 Stress–strain curve	95	(1)
6.1.1.3 Grain size	96	(1)
6.1.1.4 Strain-rate-sensitivity exponent	96	(2)
6.1.1.5 Activation energy	98	(1)
6.1.2 Alumina	99	(1)
6.1.3 Hydroxyapatite	100	(1)
6.1.4 7beta;-Spodumene glass ceramics	100	(1)
6.2 Ceramic composites	101	(8)
6.2.1 Zirconia-based composites	119
6.2.2 Alumina-based composites	105	(1)
6.2.3 Silicon nitride-based composites	106	(1)
6.2.4 Iron carbide-based composites	107	(2)
6.3 Constitutive equations and microstructures	109	(6)
6.3.1 Constitutive equations	109	(1)
6.3.2 Grain-boundary structure and segregation	110	(4)
6.3.3 Grain-boundary cavitation	114	(1)
6.4 Ingot processing route for superplastic ceramics	115	(2)
6.5 Superplasticity in geological materials	117	(2)
References	119	(6)
Chapter 7 Fine-structure superplastic intermetallics	125	(20)
7.1 Nickel-based intermetallic compounds	126	(9)
7.1.1 Nickel silicide ( Ni3Si)	126	(5)
7.1.2 Nickel aluminide ( Ni3Al)	131	(4)
7.2 Titanium-based intermetallic compounds	135	(5)
7.2.1 &alplha;2-Titanium aluminides (Ti3Al)	135	(1)
7.2.2 γ- Titanium aluminides ( TiAl)	136	(4)
7.3 Iron-based intermetallic compounds	140	(1)
References	141	(4)
Chapter 8 Fine-structure superplastic composites and laminates	145	(9)
8.1 Aluminum-based metal-matrix composites	145	(3)
8.1.1 Thermal-cycling superplasticity	147	(1)
8.1.2 Isothermal superplasticity	147	(1)
8.2 Magnesium-based metal-matrix composites	148	(1)
8.3 Zinc-based metal-matrix composites	149	(1)
8.4 Metal laminates	149	(2)
References	151	(3)
Chapter 9 High-strain-rate superplasticity	154	(35)
9.1 Experimental observations	154	(14)
9.1.1 Metal-matrix composites	154	(8)
9.1.1.1 SiC whisker-reinforced 2124 Al composite	155	(6)
9.1.1.2 Si3N4 whisker-reinforced Al composites	161	(1)
9.1.2 Mechanically alloyed alloys	162	(4)
9.1.2.1 Alumium-based alloys	163	(1)
9.1.2.2 Nickel-based alloys	164	(2)
9.1.3 Metal alloys	166	(2)
9.1.3.1 Aluminum	166	(2)
9.2 Origin of HSRS	168	(10)
9.2.1 Grain size	168	(2)
9.2.2 Interfaces	170	(8)
9.3 Cavitation in HSRS materials	178	(3)
9.4 Perspective of HSRS and deformation map	181	(4)
References	185	(4)
Chapter 10 Ductility and fracture in superplastic materials	189	(19)
10.1 Tensile ductility in superplastic metals	189	(3)
10.2 Tensile ductility in superplastic ceramics	192	(11)
10.2.1 Tensile elongation as a function of flow stress	194	(3)
10.2.2 Tensile elongation as a function of grain size	197	(1)
10.2.3 Cavitation in superplastic ceramics	198	(5)
10.3 Tensile ductility in superplastic intermetallic compounds	203	(1)
References	204	(4)
Chapter 11 Internal-stress superplasticity (ISS)	208	(11)
11.1 Whisker- and particle-reinforced composites	209	(2)
11.2 Anisotropic expanding polycrystalline materials	211	(2)
11.3 Materials undergoing polymorphic changes	213	(3)
References	216	(3)
Chapter 12 Other possible superplasticity mechanisms	219	(12)
12.1 Class I superplasticity in coarse-grained materials	219	(4)
12.2 Viscous creep mechanisms for superplasticity	223	(2)
12.3 Ultrahigh-strain-rate superplasticity	225	(3)
References	228	(3)
Chapter 13 Enhanced powder consolidation through superplastic flow	231	(8)
13.1 ISS compaction of white cast iron powders	231	(2)
13.2 FSS compaction of ultrahigh carbon steel powders	233	(1)
13.3 FSS consolidation of Ni-based superalloy powders	234	(1)
13.4 FSS extrusion and sinter forging of ultrafine ceramic powders	235	(2)
References	237	(2)
Chapter 14 Superplastic forming and diffusion bonding	239	(17)
14.1 Metals	240	(6)
14.1.1 Titanium	240	(2)
14.1.2 Iron and steels	242	(1)
14.1.3 Aluminum	242	(4)
14.2 Ceramics	246	(6)
14.2.1 Superplastic forming	246	(5)
14.2.2 Diffusion bonding	251	(1)
References	252	(4)
Chapter 15 Commercial examples of superplastic products	256	(14)
15.1 Titanium alloys	256	(1)
15.2 Nickel alloys	257	(2)
15.3 Iron alloys	259	(2)
15.4 Aluminum alloys	261	(7)
References	268	(2)
Index	270