pdf version - Home page ThiMag Scientific Pole

Strategic product innovation on global markets
Potential structural applications of
Thixomolded® magnesium
Fabrizio D’Errico
Politecnico di Milano, Department of Mechanics, Milano (ITALY)
Guido Perricone
Brembo S.p.A., Advanced Research, Stezzano (ITALY)
Who are we? Fabrizio D’Errico…
• The Politecnico di Milano was founded in 1863
• Today, it occupies the 66thposition on TOP100
Engineering & IT World University(*)
• In 1982 the former Institute of Mechanics inside
Politecnico di Milano became the Department of
Mechanical Engineering
• I’m an Assistant Professor in the Research Group
Materials for Mechanical Applications (one of the
six Departments’ Research Groups)
(*) [Source: THES-QS World University Ranking 2007]
2
Dept of Mechanical Engineering
Who are we? Guido Perricone…
• Brembo was founded in 1961. At present, Brembo
employees over 5700 people, nearly 9% of which
are engineers and product specialists working in
research and development.
• Brembo is the world leader in the design and
manufacturing of high performance braking
systems and components.
• Brembo currently operates in 3 continents with
production plants in 11 countries
• I’m in charge for Material Development in the
Advanced Research.
• I’ve been collaborating with Politecnico di Milano
Department of Mechanical Engineering with Fabrizio
D’Errico’s staff since 2004.
3
Dept of Mechanical Engineering
Research topic inherent in the discussion
Main topics on ultralight-alloys researches
• Influence of microstructure on mechanical behavior of
Thixomolded® magnesium alloys
• Modeling & design of magnesium thixomolded parts
• Cost-benefit evaluation on widespread use of magnesium
for structural applications
4
Dept of Mechanical Engineering
Main goals of research on magnesium alloys
Year 2006
Scope of research: Feasibility study of AZ91D structural application
Goal: Realizing of MAGMA bike-saddle
Customer: Selle San Marco S.p.A.
Intermediate goals:
•Material characterization (AZ91D-thixomolded)
•Modeling of simulated tests
•Design & optimization of component by CAE
5
Dept of Mechanical Engineering
Main goals of research on magnesium alloys
Year 2007
Scope of research: Influence of microstructure on fatigue properties of a
Thixomolded® AZ91D magnesium alloy
Goal: Development of cheaper heat treatment to increase poor ductility of the AZ91D
[Results were discussed at “7th International Conference of Fracture Mechanics(1)”]
Customer: University research (Graduate Thesis)
Intermediate goals:
•Comprehension of fatigue damage mechanism of Thixo-AZ91D
•Optimizing Tx treatment to increase ductility of Thixo-AZ91D
•Investigation on static and dynamic mechanical properties of a Thixo-AZ91D (assupplied) and a Thixo-AZ91D-Tx heat treated
(*) Reference: F.D’Errico, M. Boniardi, G. Perricone, D. Vujanovic, Influence of microstructure on mechanical
properties of an AZ91D thixomolded magnesium alloy, Key Engineering Materials, Vols. 348-349 (2007)
6
Dept of Mechanical Engineering
Main goals of research on magnesium alloys
Year 2008
Scope of research: Study of effect of Tx treatment on fracture
toughness
Goals: 1)Fracture toughness data for Thixo-AM60B, AZ91D and AZ91D-Tx
2)Comprehension of microstructure parameters affecting toughness
Customer: University research in collaboration with POLO REGIONALE di LECCO
of Politecnico di Milano
(Research staff: Fabrizio D’ERRICO, Barbara RIVOLTA, Riccardo GEROSA)
Intermediate goals:
• Small specimens methodology test set-up for Paris Law (crack-propagation tests)
7
Dept of Mechanical Engineering
Main goals of research on magnesium alloys
Year 2008 (April)
Scope of research: Feasibility study on potential widespread structural
uses of Thixomolded® magnesium alloys
Goal: Determination of technological and economical barriers to
magnesium uses
Customer: University research (Graduate Thesis)
Intermediate goals:
…
8
NOW, we’re going to talk about…
Dept of Mechanical Engineering
Background
Magnesium alloys
candidates as the
ultralight-weight
metallic material
LIGHTWEIGHT
LIGHTWEIGHT
65%
of
aluminum
65% of aluminum volumic
volumic mass
mass
Availability
Availability
Endless
supplying
Endless supplying (8th
(8th hearth
hearth element)
element)
Highest
Highest specific
specific strength
strength (strength
(strength to
to volumic
volumic mass)
mass)
High
High castability
castability
High
High speed
speed machining
machining
Case histories show
magnesium
automotive market
does not yet
exponentially start
9
Low ductility
High costs
Low toughness
Low experience
Low corrosion resistance
Few specialist suppliers
Low creep resistance
Few specialist transformers
High flammability
Technical doubts
Dept of Mechanical Engineering
Lack of trust
What’s the future for magnesium in structural
application?
Technical doubts
Lack of trust
Low ductility
High costs
Low toughness
Low experience
Low corrosion resistance
Low creep resistance
High inflammability
Few specialist suppliers
Durability
High temperature
Toughness
History
Availability
Magnesium price
Barriers to magnesium market
10
Dept of Mechanical Engineering
Technical barriers
DURABILITY: Corrosion – General issues
BARRIERS
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Corrosion resistance of the bare metal has had a major improvement with the
introduction of the high purity alloys (some ppm for Cu, Fe, Ni and Co)
AZ91D (left) and AZ91B (right) uncoated after
10 days of salt spray exposure [ASM Handbook]
Same corrosion resistance of aluminum A380 (Al4250)
[Hydro Magnesium: Corrosion and Finishing of Magnesium Alloy]
Moreover, there are a lot of protection systems that offer a wide range of coating
possibilities. We want to remember: anodic treatments (e.g.: the “old” DOWs and
the “new” ceramic chrome free ones) and multi-layers organic finishing.
Message is that the same choice that we have for aluminum alloy, exist also for
magnesium alloy but, we have to know them!
However, the main problem is the GALVANIC CORROSION. It can be successfully
faced if proper countermeasures are taken.
11
Dept of Mechanical Engineering
Technical barriers
DURABILITY: Corrosion – Thixomolding alloy
BARRIERS
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Thixomolding alloy can help in corrosion
issue because we have observed
aluminum enrichment on the asthixomolded surface, respect to the
average alloy composition. It could
improve the corrosion resistance respect
to the same alloy made by HPDC.
However this is an issue that has to be
better understood.
12
Dept of Mechanical Engineering
Technical barriers
Heat resistant alloys
Development of magnesium alloys with better high temperature performance
BARRIERS
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Case history
Volkswagen Beatle (1960),
ternary Mg-alloy (Mg-Al-Si)
From the past…
…to present:
BMW 3lt, 6 cylinders engine block (2007), ternary Mg-alloy (Mg-Al-Sr)
13
Dept of Mechanical Engineering
Technical barriers
TOUGHNESS
BARRIERS
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Background
Low ductility (and toughness) for magnesium alloys due to:
•
•
Intrinsic low ductility for crystal structure (lattice) of magnesium
Lower “deformation possibilities” offered to magnesium lattice because of
HCP (Hexagonal Closed Packed)
HCP (Magnesium)
FCC
(austenitic stainless steels)
BCC
(most of steels)
PRIMARY BRITTLESS
For intrinsic brittleness due
to its crystal lattice
3D model of Mg grains
14
Dept of Mechanical Engineering
2D model of Mg grains
Technical barriers
TOUGHNESS
Other reasons for magnesium alloys low ductility and toughness:
•
•
•
Internal defects due to technological process (gas porosities, shrinkage cavities)
Increasing aluminum content in Mg alloysÆ large amount of Mg17Al12- phase on grain
boundaries
Mg17Al12 increase brittle behavior because its own brittleness and incoherency (i.e. it
does not well join to the Mg-matrix )
Mg17Al12 compound
partially dissolved by Tx
Gas porosity
Mg17Al12 -phase
SECONDARY BRITTLESS depending on microstructural “defects”
15
Dept of Mechanical Engineering
Technical barriers
TOUGHNESS
ACTIONS
Investigation on ductile properties on Al-Mg system is accomplished Æ
partial dissolving of Mg17Al12 leads to increase of ductility
Data results
• Thixo-AM60B, as supplied Æ Elongation: 13%
• Thixo-AZ91D, as supplied Æ Elongation: 8%
• Thixo-AZ91D-Tx Æ Elongation: 12%
Accomplished the Paris Law (crack-propagation and KIc evaluation):
Results: no increase in fracture toughness has been obtained for
AZ91D-Tx in comparison with AZ91D as supplied, but higher for AM60B
SECONDARY BRITTLESS depending mostly by presence of Mg17Al12
16
Dept of Mechanical Engineering
Technical barriers
TOUGHNESS: Summary
Low toughness
of magnesium alloy
PRIMARY BRITTLESS
SECONDARY BRITTLESS
Intrinsic brittleness of HCP
depending mostly by
crystal lattice
presence of Mg17Al12
ACTION
ACTION
Hypothesis: REFINING
(Decreasing grain dimension)
Ternary alloy with refining elements
17
Example: •
Rare Hearts,•
Sr, Si, etc
Dept of Mechanical Engineering
Reduce Mg17Al12 content
Reduce porosity
• Reduce shrinkage microcavities
History
SOURCES:
Producer reports
BARRIERS
Investor reports
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Economical area articles
Market data report
Famous anecdotes
Historical analysis of
magnesium market
Milestones
Misunderstanding episodes
•
•
Analysis of
Current Scenario
Parameters:
Magnesium production
Technical errors
Type of Mg-alloys available
BARRIERS to Mg-market
18
Dept of Mechanical Engineering
FUTURE SCENARIO
History analysis: EXAMPLE OF ANECTODES
BARRIERS
19
DOW Chemical
B29 Fortress
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Magnesium Division
Engine exploded
Exit of market on 1998
due to Mg flammability
•
Ignition problem
•
Magnesium at melting temperature is very
oxygen reactive
•
Problem not solved by early test-flights
•
Bomber was forced to flight in any cases
Dept of Mechanical Engineering
because Mg-price was too high
•
During and after: World Wars, Corea, Vietnam
DOW acted on (quasi) monopolistic market
•
Many plants closed after WARS for demand
decreasing
•
After Corea and Vietnam, USA Govern decided
NOT TO stock other magnesium for strategic
reserve
•
Open market and rise of new GLOBAL
PRODUCERS (CHINA, ISRAEL, RUSSIA, …)
MARKET PRICE ANALYSIS: Depending on availability
Durability
High temperature
Toughness
History
Availability
Magnesium Price
SOURCE (2001)
The Impact of Increased Automotive
Interest on the World Mg Market
1000 tonn
BARRIERS
Randall J.Urbance ,
Massachutes Institute of Technology
Year
The problem with dynamic supply and demand interaction
$1.80
$1.60
$1.80
$1.50
$1.70
$1.60
$1.30
$1.20
supply
demand
$1.10
$1.00
0
200
Massachusetts Institute of Technology
Cambridge, Massachusetts
400
600
800
Mg Rate (ktpa)
1,000 1,200
$1.80
$1.50
$1.70
$1.40
$1.60
$1.30
$1.20
supply
Mg Price ($/lb)
$1.40
Mg Price ($/lb)
Mg Price ($/lb)
$1.70
supply demand
$1.10
$1.00
0
200
400
600
800
Mg Rate (ktpa)
1,000 1,200
Materials Systems Laboratory
Massachusetts Institute of Technology
Cambridge, Massachusetts
$1.50
Large price swing
Demand may fall
$1.40
$1.30
$1.20
supply
Dept of Mechanical Engineering
demand
$1.10
Materials Systems Laboratory
$1.00
0
200
Massachusetts Institute of Technology
Cambridge, Massachusetts
20
supply demand
400
600
800
Mg Rate (ktpa)
1,000 1,200
Materials Systems Laboratory
Market scenario and critical variables
BARRIERS
•
•
Price rises for over-demand (growth over-capacity)
Action: new INVESTORS and NEW PRODUCERS
Durability
High temperature
Toughness
History
Availability
Magnesium Price
Capacity Utilization
Medium Term Supply Expansions
200%
150%
Large demand spike fueled by
low prices and auto interest
Growing
overcapacity
100%
50%
$2.60
Capacity Utilization
$2.40
Modeled Pure Price
Mg Price ($/lb)
$2.20
Material prices drop to
extremely low levels
$2.00
Modeled DCA Price
$1.80
$1.60
$1.40
$1.20
$1.00
1990
1995
2000
2005
2010
2015
Year
New agreements between
INVESTORS and PRODUCERS
•
Wrong 2008 scenario: WHY?
have been changing supply for 2008
(Source: Market Magnesium World Bulletins)
21
Dept of Mechanical Engineering
CONCLUSION
Reduced barriers to magnesium market
Lack of trust
Technical doubts
Durability
Too much wrong belifes
Innovation on Mg
alloys materials
High temperature
Toughness
History
Availability
Magnesium price
22
Dept of Mechanical Engineering
Research on Primary
and Secondary brittleness
New alloys
NEW PLANTS
due to increasing demand
Actual COST Strategy
Cost analysis for magnesium part…
…Should not be limited to material price!
•
High productivity technologies are able to decrease product cost
ƒ
•
Reduced in SUPPLY CHAIN steps
ƒ
•
23
Thixomolding is candidate with HPDC process (net-near-shape forming)
Thixomolding against HDPC can simplify (avoid) assemblage
Future scenario of material availability should consider RECYCLING
MATERIAL
Dept of Mechanical Engineering
Actual COST Strategy
However, make the right cost analysis of the
PRODUCT!
Properties
(Kg/dm3)
Volumic mass
Fatigue endurance (MPa)
Volume (dm3)
Weight (Kg)
$ / Kg
$ / dm3
Aluminium alloy
Magnesium alloy
2,74
∼90 (HPDC)
100
274
3
8,22
1,74
∼ 90 (AZ91D Thixomolded)
100
174
5
8,70
Also if considered actual
Mg high price
24
Dept of Mechanical Engineering
VALUE ANALYSIS for strategic innovation
You should not act (only) for cost advantage!
Best get COMPETITIVE ADVANTAGE by
DIFFERENTIATION strategy
•
Thixomolding® Process is an ideal candidate to elaborate new FUNCTIONAL
SHAPE thanks to a quasi-blank-sheet design
•
Product innovation leads to the differentiation advantage in automotive, thanks to:
• ULTRALIGHT MATERIAL & MORE COMPLEX GEOMETRY AVAILABLE
• STRUCTURAL PARTS weight reduction = strong weight reduction on vehicles!
• Strong weight reduction Æ decrease emissions (goals of KYOTO Protocol and new
EU regulation)
• Reducing weight Æ Increasing efficiency, specially for un-conventional vehicle
25
Dept of Mechanical Engineering
Conclusion
To increase use of magnesium alloys for
(automotive) STRUCTURAL applications, it needs
everyone plays its role!
(THEY)
SCIENCE
Investors
(WE)
Project for Research Pole
(YOU)
for Thix-Mg at Milano-Lecco
New SCENARIO
When?
NOW!
26
Dept of Mechanical Engineering
Contacts
Fabrizio D’Errico
Politecnico di Milano
Department of Mechanics
Via La masa, 1
20156 MILAN (ITALY)
[email protected]
Guido Perricone
Brembo S.p.A.
Viale Europa, 2
20040 Stezzano (ITALY)
[email protected]
Authors wish thank to Dragutin Vujanovic (Thixotec-Europe B.V.)
for supplying material samples and for his encouragement and
support to us.
27
Dept of Mechanical Engineering