TY - JOUR

T1 - Influence of PVD-coating technology and pretreatments on residual stresses for sheet-bulk metal forming tools

AU - Tillmann, Wolfgang

AU - Stangier, Dominic

AU - Denkena, Berend

AU - Grove, Thilo

AU - Lucas, Henning

N1 - Funding information: The authors gratefully acknowledge the financial support of the German Research Foundation (DFG) within the transregional collaborative research center TR73 “Manufacturing of complex functional components with variants by using a new sheet metal forming process—Sheet Bulk Metal Forming”. This work is a cooperation of the subprojects B5 (Application of nanostructured bionic thin layers to enhance the wear and friction behaviour of forming tools by thin-walled sheet forming) and B8 (Grinding strategies for local and stress orientated subsurface-modification of sheet-bulk metal forming tools).

PY - 2016/2

Y1 - 2016/2

N2 - Residual stresses in the substrate material are significantly influencing the performance of PVD-coated parts and tools which are exposed to high forces. Especially for forming operations, such as sheet-bulk metal forming, during which normal contact pressures of 1.4 GPa can occur, the reduction of friction and, at the same time, the wear protection by means of thin Cr-based coatings are essential. To ensure a long service life of forming tool and tool coating, each step of the substrate pre-treatment, as well as the magnetron-sputtering process, has to be coordinated and compatible. Therefore, polished as well as nitrided samples consisting of high-speed steel (AISI M3:2) are exposed to a sequence of plasma-based pre-treatments prior to depositing a CrAlN coating. Hardness and Young’s modulus of the substrate and the coating are analysed by means of nanoindentation. To determine the adhesion between coating and substrate, scratch tests are conducted and analysed using a scanning electron microscope. For each step, the residual stresses are determined using sin2ψ measurements, which are correlated to the mechanical properties. A plasma-nitriding process before the CrAlN coating induces high compressive residual stresses into the sample subsurface and at the same time increases the hardness of the surface. This results in higher critical loads during the scratch tests and therefore a better adhesion of the coating on the substrate.

AB - Residual stresses in the substrate material are significantly influencing the performance of PVD-coated parts and tools which are exposed to high forces. Especially for forming operations, such as sheet-bulk metal forming, during which normal contact pressures of 1.4 GPa can occur, the reduction of friction and, at the same time, the wear protection by means of thin Cr-based coatings are essential. To ensure a long service life of forming tool and tool coating, each step of the substrate pre-treatment, as well as the magnetron-sputtering process, has to be coordinated and compatible. Therefore, polished as well as nitrided samples consisting of high-speed steel (AISI M3:2) are exposed to a sequence of plasma-based pre-treatments prior to depositing a CrAlN coating. Hardness and Young’s modulus of the substrate and the coating are analysed by means of nanoindentation. To determine the adhesion between coating and substrate, scratch tests are conducted and analysed using a scanning electron microscope. For each step, the residual stresses are determined using sin2ψ measurements, which are correlated to the mechanical properties. A plasma-nitriding process before the CrAlN coating induces high compressive residual stresses into the sample subsurface and at the same time increases the hardness of the surface. This results in higher critical loads during the scratch tests and therefore a better adhesion of the coating on the substrate.

KW - CrAlN

KW - High-speed steel 1.3344 (AISI M3:2)

KW - Pre-treatment

KW - PVD-technology

KW - Residual stresses

KW - Sheet-bulk metal forming

UR - http://www.scopus.com/inward/record.url?scp=84957838464&partnerID=8YFLogxK

U2 - 10.1007/s11740-015-0653-4

DO - 10.1007/s11740-015-0653-4

M3 - Article

AN - SCOPUS:84957838464

VL - 10

SP - 17

EP - 24

JO - Production Engineering

JF - Production Engineering

SN - 0944-6524

IS - 1

ER -