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Mechanical characterization of innovative structural materials

Microstructure of nickel base single crystal SMP14 superalloy, after heat treatment (a), and after 400h of creep at 1050°C/150
1) Microstructure of nickel base single crystal SMP14 superalloy, after heat treatment (a), and after 400h of creep at 1050°C/150
TEM micrographs of crept strained Nimonic 263 at 700° C/380 MPa; (a) dislocation tangles; (b) staking fault; (c) grain boundary precipitation
2) TEM micrographs of crept strained Nimonic 263 at 700° C/380 MPa; (a) dislocation tangles; (b) staking fault; (c) grain boundary precipitation
TEM micrographs of crept strained Nimonic 263 at 900° C/55 MPa: (a) and (b) γ’ particles of ~250 nm average size and dislocation nodes; (c) grain boundary locked by a γ’ particles
3) TEM micrographs of crept strained Nimonic 263 at 900° C/55 MPa: (a) and (b) γ’ particles of ~250 nm average size and dislocation nodes; (c) grain boundary locked by a γ’ particles
TEM microstructure of TiAl-8Nb after creep at 700°C/350 MPa: (a) high density of dislocations and twinning: zone axis: B=[0-11]; (b) magnification of fig. 3(a), dislocation activity inside the γ lamellae; (c) diffraction image: it is clear the superimp
4) TEM microstructure of TiAl-8Nb after creep at 700°C/350 MPa: (a) high density of dislocations and twinning: zone axis: B=[0-11]; (b) magnification of fig. 3(a), dislocation activity inside the γ lamellae; (c) diffraction image: it is clear the superimp
Dislocation structure inside the AISI316L alloy. The alloy was strained at 0.09. at T= 1000°C and at 0.006 s-1 a strain rate
5) Dislocation structure inside the AISI316L alloy. The alloy was strained at 0.09. at T= 1000°C and at 0.006 s-1 a strain rate
Analysis of dislocation walls in AISI 316L . The alloy was strained at 0.09. at T= 1000°C and at 0.006 s-1 a strain rate
6) Analysis of dislocation walls in AISI 316L . The alloy was strained at 0.09. at T= 1000°C and at 0.006 s-1 a strain rate
Identification of brittle χphase and determination of thecrystallographic relationship among χparticles and the ferritic δ and austenitic γmatrix
7) Identification of brittle χphase and determination of thecrystallographic relationship among χparticles and the ferritic δ and austenitic γmatrix

The Mechanical Characterization group is working in the field of high temperature alloys since the early ‘70 gaining an extensive experience in lifetime investigation involving creep, low cycle and thermo-mechanical fatigue and crack propagation testing. A considerable experience has been achieved in examination of mechanical properties and microstructure in a wide range of gas turbine materials, such as sheet materials for combustors, wrought disk alloys, conventionally cast, directionally solidified, single crystal alloys for blades and vanes, creep resistant titanium alloys, TiAl base intermetallic compounds and dispersion strengthened alloys.
The mechanical properties (creep, low cycle and thermo-mechanical fatigue, creep and fatigue crack propagation) are analysed and the parameters necessary for component design and models for life prediction are evaluated and microstructure characterization is performed to gather physical parameters to cast such models.
The scientific activity, generally carried out in the frame of European or National research programs, is mainly oriented in the following three directions:

  • Development of user friendly constitutive equations able to describe the high temperature behaviour of alloys
  • Support to the development of new alloys for high temperature applications
  • Analysis of strain and damage mechanisms at high temperatures

As a consequence of the past undertaken research programs, the group take advantage of  a vast range of facilities, capabilities and expertise which can be assembled in advanced research activities and, particularly in the last years, to satisfy the most demanding customer requirements.

Facilities

  • 3 electrohydraulic material testing systems up to 250 kN for mechanical testing in air and in vacuum from room temperature to 1200°C
  • 4 electromechanical material testing systems up to 100 kN for mechanical tests at temperature up to 1150°C
  • 1 rotating bending machine for tests in air up to 980°C
  • 11 creep testing machines up to 1150°C
  • X ray diffractometer X SIEMENS D5000
  • Scanning electron microscope STEREOSCAN 430 by LEO with a system of energy dispersion spectroscopy EDS-INCA by Oxford Instruments
  • Analytical Transmission electron microscope (TEM) JEM 2000FXII by JEOL with a maximum accelerating voltage of 200kV

Documents

Contracts

Main international research programs

  • BE97-4650: MANUFACTURE OF DUAL ALLOY TURBINE ENGINE DISKS (MANDATE), July 1998 – December 2002
  • EC Concerted Action COST522: ULTRA-EFFICIENT, LOW EMISSION POWER PLANT INTO THE 21ST CENTURY: WP 1.1 Blades and Vanes: High Temperature Mechanical Properties of Nickel-base Superalloys for Gas Turbine Blades, Project n° I 102, 1999-2003
  • EC Concerted Action COST522: ULTRA-EFFICIENT, LOW EMISSION POWER PLANT INTO THE 21ST CENTURY: WP 1.2 Blades and Vanes: Gamma TiAl, Project n° I 101, 1999-2003
  • EC 5th FP GROWTH: G5RD-CT-2002-00819: EXPANDING THE LIMITS OF SINGLE CRYSTAL SUPERALLOYS THROUGH SHORT CRACK FRACTURE MECHANICS ANALYSIS (SOCRAX), December 2002- November 2006
  • EC Concerted Action COST 538: HIGH TEMPERAURE PLANT LIFETIME EXTENSION, 2004 - 2008
  • EC 6th FP IP IMPRESS – NMP3: INTERMETALLIC MATERIALS PROCESSING IN RELATION TO EARTH AND SPACE SOLIDIFICATION (IMPRESS), 2004 – 2009

Main national research programs

  • ANSALDO ENERGIA contract: CREEP BEHAVIOUR OF A TURBINE DISK ALLOY, 2010- 2012
  • ANSALDO ENERGIA contract: PANDA – CREEP, TMF AND LCF STUDIES OF RENE’ 80 Ni-BASE SUPERALLOY FOR ADVANCED GAS TURBINE BLADE, 2005-2009
  • AVIO SpA contract: TENSILE, CREEP, LCF AND MCROSTRUCTURE STUDIES OF HAYNES 230 Ni-BASE SUPERALLOY, 2006-2008
  • EMA SpA contracts, FAR MITGEA: CREEP BEHAVIOUR ANALYSIS OF THE NICKEL BASE SUPERALLOY CMSX 486, 2006-2010
  • FIRB MITGEA contract RBIP064N2X: STUDY OF NEW MATERIALS FOR GAS TURBINES OF VERY HIGH EFFICIENCY AND REDUCED ENVIRONMENTAL IMPACT, 2007-2011
  • Mangiarotti Nuclear contract: RESIDUAL STRESS ASSESSMENT THROUGH XRD TECHNIQUES, 2010-2011

Contacts

  • Dr. Giuliano Angella, phone +39 02 66173 327
  • Dr. Maurizio Maldini, phone +39 02 66173 330
  • Dr. Dario Ripamonti, phone +39 02 66173 323
  • Dr. Riccardo Donnini, phone +39 02 66173 365
  • Davide Della Torre, phone +39 02 66173 404
  • Tullio Ranucci, phone +39 02 66173 401
  • Enrico Signorelli, phone +39 02 66173 378
  • Dr. Valentino Lupinc (associate), phone +39 02 66173 329

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