从相图到材料成份设计-

essentially discrete diffraction diagram.
"periodic crystals" : periodic on the atomic scale, and "aperiodic crystals" : not periodic on the atomic scale "quasi-crystals “: a special group of "aperiodic crystals"
multi-component phases with narrow composition ranges
Binary-ternary-quaternary evolutions
B 100
10
90 20 Our approach: 80
from simple70systems to complex systems
60 50 60 40
30
AxBy + Path = AuBvCw
40 50
AxBy
30
20
Path
AuBvCw
70 80 90
10 100
100 A
90
80
70
60
50
40
30
20
10
C
Why are we interested both in QCs and BMGs?
1. Academic and practical interests
Extremely soft magnetic => transformer cores, flexible shieldings Mechanically hard => hard coatings, no large scale applications due to strain softening Ductility (free volume) + no precipitations + adjustable composition (high solubility limit) => soldering foils No grain boundaries => corrosion protection annealing leads to embrittlement rapid cooling results in small dimensions at least in one dimension raw materials and production are expensive
Result of a computer simulation of a binary amorphous Co-Zr alloy
Comparison between experiment and simulation
Properties and Applications:
Conventional metallic glasses
Criterion 1:
-1.5
Fe（-2） -1.7 -1.4 -1.1 -0.8
e/a-constant line
Dong, Scr. Met & Mat 1995
0.0 0.5 b 1.0 1.5 -0.5
-1.0
-0.5
-0.2 0.1 0.4
Al13Fe4
2.0 α
d-Al6Fe
2.5

•Formations of amorphous and quasicrystal phases in Ti-Zr-Ni-Cu alloys Wang, L. Ma, L. Ma, C. Inoue, 2003 •Study of the Quasicrystal Formation in Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Soubeyroux, J. L. Pelletier, J. M. Van de Moortele, B. Epicier, T. 2002 •Quasicrystal Formation, Phase Selection and Crystallization Kinetics in Zr-CuNi-Al Based Metallic Glasses Koster, U. Zander, D. Janlewing, R. 2002
golf clubs helium and neon catcher optical parts aircraft components armor-piercing bullets
Phase composition rules:
Dream of materials researchers!
Phase composition rules in multicomponent systems?
Icosahedral point group
Electronic phase e/a=1.86
Ordered solid
An Al-Cu-Fe icosahedral phase grain with the football shape
Paul J. Steinhardt
Properties and Applications
• metallic glasses: – Binary: Zr-Ni, Zr-Cu… – Ternary: Zr60Al20Ni20 , Zr65Cu27.5Al7.5, – Quaternary: Zr65Al7.5Ni10Cu17.5 (Inoue), Ti34Cu47Zr11Ni8 – More: Zr52.5Ti5Cu17.9Ni14.6Al10, Zr41.2Ti13.8Cu12.5Ni10Be22.5, Zr58.5Nb2.8Cu15.6Ni12.8Al10.3
Why are we interested both in QCs and BMGs?
1. Academic and practical interests 2. They are structurally inter-related
•Roles of local icosahedral chemical ordering in glass and quasicrystal formation in metallic glass formers Tanaka, H. 2003
Advent of Bulk Metallic Glasses
Applications of BMGs
•High strength-to-weight ratios, •High hardness, •Excellent wear properties, •Good forming and shaping qualities, •Special chemical absorption •Unusual magnetic properties
• quasicrystals
– Binary: d-Al6Fe, d-Al4Ni , i-Al6Mn, d-Al4Mn, i-Ti2Fe
– Ternary: i-Al62.5Cu24.5Fe13, i-Al69Pd22Mn9,
d-Al67.5Pd14Mn18.5, i-Zr45Ti38Ni17 …
definition of “quasicrystal"
A diffraction diagram of a periodic crystal can always be indexed as a vector sum with with three integer coefficients (h,k,l) as hb1+ kb2+ lb3. A quasicrystal needs more than three wave vectors to generate all the diffraction peaks.
源自文库
相
c
a= 0.3209 nm c= 0.5210 nm
a
120°
b
Hexagonal structure of Magnesium
Phase Diagrams, the phases present at a given temperature and composition
Fe-C phase diagram
• Quasicrystals: Hume-Rothery phases
G ＝ U － TS
1、Electrochemical； 2、Atomic size； 3、Valence electron.
Electronic phase (2kf ~ K)
AlCuFe QC： 2kf ＝ 30.4 nm-1 e/a = 1.86 K ＝ 29.8 nm-1 K ＝ 31.3 nm-1
Poor thermal and electrical conductors Thermal barrier coating for engines Hydrogen absorption storage materials Low surface energy Sitram Cybernox2 Covered Saucier non-stick cooking pan Price:$149.99 High hardness strengthening particles in alloys and in composites surgical instruments, electric razors, artificial joints
从相图到材料成分设计： Composition rules of amorphous alloys and quasicrystals
董Dong 闯Chuang Dalian Univ. of Tech., China
大连理工大学学术讲演会，2004年5月12日
Structure Property Applications
Al7Cu2Fe
IQC
Al10Cu9Fe
e/a-constant e/a=1.86 Al4Cu9 ζ 2
1.8 1.6 1.4
0.7 (Cu)
Al (+3)
2.8
2.6
2.4
θ
2.2
2.0
1.2
Cu (+1)
Al-Cu-Fe e/a diagram
Zr-Ti-Ni
Ti
Ti 100
W-phase (Bergman phase)
The 10-fold Penrose tiling constructed with two kinds of tiles, fat and thin rhombi.
• Quasicrystals are intermetallic compounds
Intermetallic with specific composition Al62.5Cu24.5Fe13
Isothermal section: Al-Ni-Zr system
Ni36Zr64 Ni24Zr76
Generalities about quasicrystals & amorphous solids
new definition of "crystal"
In 1991, the International Union of Crystallography decided to redefine the term "crystal" to mean any solid having an
Brittle
Amorphous structures
Pair correlation function (= number of neighbors in a given shel
Model+ simulation+ experimental observation
Atomic structures
Why are we interested both in QCs and BMGs?
1. Academic and practical interests 2. They are structurally inter-related 3. They are subsystem-based
d-Al6Fe i-Al62.5Cu24.5Fe13 Zr-Ni Zr60Al20Ni20 Zr65Al7.5Ni10Cu17.5