Synthesis of physical and mechanical behaviour in metal-matrix materials with heterogeneous microstructure Audrius Jutas Kaunas University of Technology, Lithuania KTU, Faculty of Mechanical Engineering, Department of mechanics of solids Address: Kęstučio 27, Kaunas LT-3004, Lithuania Tel.: , fax.:

Department of Mechanics of Solids The Department was founded in The material testing laboratory of this department in 1920 met the world standards and was the best in the Baltic countries. The first Lithuanian textbook on strength of materials was published in 1935 (author Prof. K.Vasiliauskas). In September 1, 1993 this department was named as Department of Mechanics of Solids. Its science and studies trends differ from the predecessor by a more expansive curriculum that combines the problems of strength of materials and structures, durability, fracture mechanics, stability, and it is a part of the area of mechanical reliability of structures.

Department activity presents 11 monographs; 9 textbooks; More than 2000 scientific articles International projects Participation in International Scientific Organizations Establishment of Strength and Fracture mechanics centre

Staff Age Average of Staff is 38 Years Professor hab. dr. Antanas Ziliukas Assoc. Professorsdr. Audrius Jutas dr. Vytautas Vasauskas, dr. Kazimieras Petkevicius dr. Vitalis Leisis dr. Arturas Kersys dr. Saulius Diliunas LecturerDr. Paulius Griskevicius AssistantsDr. Nerijus MeslinasVytautas Capas ScientistDr. Daiva Zeleniakiene Doctoral StudentsNeringa KeršienėMindaugas Bereisa Master StudentDeividas Liaudaitis

Areas of studies programme in department Strength of materials and structures, Mechanics of Materials, Fracture mechanics, Stability, Reliability, Finite Elements

I. Introduction Defects of heterogeneous materials occur at different spatial scales and can have different origin, similar to the corresponding hierarchy of heterogeneous displacement fields caused by lattice defects in the bulk during plastic deformation There is important to define how the fundamental knowledge can be joined together with the use of different length scales.

II. Objectives The aim of the project is to understand the phenomena of deformation behaviour in metal-matrix materials from nano- to macro-scale The study should to join the investigations of interfacial or intrinsic phenomena in heterogeneous microstructures, e.g. ferite-perlite microstructures, because these in multifunctional structures are used

III. Project realization 1. First step Problems solving in nano-scale 2. Second step Problems solving in micro-scale 3. Third step Problems solving in macro-scale

1.First step: Problems solving in nano - scale A. Clear selection of lattice type B. Clear separation of material defects C. Clear separation of deformation behavior of lattice

A. Clear selection of lattice type E.g.: Ferrite-perlite microstructure of steel AISI 1144

B. Clear separation of material defects Defects that are given after metal alloy fabrication: Nano-structural defects (point defects, elastic distortion e.g. near two grain boundary) Expected result: Evaluation of defects type and density

C. Clear separation of deformation behavior of lattice Atom positions of deformed lattice in elastic state (returnable) Atom positions of deformed lattice in an intermediate state (atomic displacements by single dislocations) Atom positions of deformed lattice in plastic state (large crystallographic slip steps created by sets of collectively gliding dislocation on parallel or identical glide planes; twins formation)

C. Clear separation of deformation behavior of lattice (continued) Expected result: Choosing of models for a calculation of lattice deformation Assessment of lattice constants, bond energy between the atoms, interatomic force, Burger’s vector, shear stress, diffusion and others

C. Clear separation of deformation behavior of lattice (continued) In conclusions it should be asked: What impact mechanism to neighborhood lattice should be proposed? What physical and mathematical relationship is between investigated members? What members will be used for an assessment of micro- mechanical behavior?

2. Second step: Problems solving in micro-scale How much of different micro-components in calculating volume Axes orientation of several grains Fine measurement of grain dimensions Micro-structural model creation using mean values of grain sizes and axiality

Problems solving in micro-scale Expected result: Choose the models on micro-structural assessment for calculation of grain deformation Evaluation of micro-mechanical behavior using classical (analytics) and modern methods of calculation (software, e.g. ABAQUS) Separation analysis of elastic and plastic states in micro-structural components (grains)

Problems solving in micro-scale In conclusions it should be asked: What impact mechanism to neighborhood grain is given? What mathematical relationships should be choosing due to deformation of grains? What members will be used for an assessment of macro-mechanical behavior?

3. Third step: Problems solving in macro-scale Experimental assessment of mechanical properties using stress- strain diagram (  pr,  e,  Y,  u,  fr, E, E t, E p, ,  )

Problems solving in macro-scale Expected result: Separation of elastic and plastic macro-mechanical properties of heterogeneous material Assessment of strain points at which the global macro- mechanical energy of attraction and repulsion will occur.

Problems solving in macro-scale In conclusions it should be asked: What relationship between nano-, micro- and macro- mechanical behavior? What quantitative values are used for “step by step” assessment due to uniaxial deformation of heterogeneous material? What members of different scales could be bridged together?

IV. Instruments for project realization 1. First step X-Ray diffraction analysis, Simulation of lattice deformation and calculation 2. Second step Micro-structural analysis, measurement of grain size, simulation of grain deformation and calculation 3. Third step Stress-strain diagram, calculation of macro-mechanical members

What changes could be in potential energy U and compressibility 1/E using stress- strain diagram?

V. Offered expertise Research group from KTU can offer the solutions for formulating and modelling of mechanism of nano - structured materials with metal-matrix

VI. Partner search 1. Partners in the field of solid state physics to realize the investigation of nano - scale atom structures (complex lattice deformation, X-ray diffraction); 2. Partners in the field of materials engineering (investigations of microstructure) 3. Partners in the field of application of computational methods (obtain the results of simulation by suggested algorithm)

Thank You for Your attention! KTU, Faculty of Mechanical Engineering, Department of mechanics of solids Address: Kęstučio 27, Kaunas LT-3004, Lithuania Tel.: , fax.: