Instrumented and Vickers Indentation for the Characterization of Stiffness,Hardness and Toughness of Zirconia Toughened Al2O3 and SiC Armor
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2015年第8期
论文作者：Aleksandra Nastic Ali Merati Mariusz Bielawski Olaniyi Fakolujo Michel Nganbe
文章页码：773 - 783
摘 要：Instrumented and Vickers indentation testing and microstructure analysis were used to investigate zirconia toughened alumina（ZTA） and silicon carbide（SiC）.Several equations were studied to relate the Vickers indentation hardness,Young’s modulus and crack behavior to the fracture toughness.The fracture in SiC is unstable and occurs primarily by cleavage leading to a relatively low toughness of 3 MPa m1/2,which may be inappropriate for multi-hit capability.ZTA absorbs energy by plastic deformation,pore collapse,crack deviation and crack bridging and exhibits time dependent creep.With a relatively high toughness around 6.6 MPa m1/2,ZTA is promising for multi-hit capability.The higher accuracy of mediar equations in calculating the indentation fracture toughness and the relatively high c/a ratios above 2.5suggest median type cracking for both SiC and ZTA.The Young’s modulus of both ceramics was most accurately measured at lower indentation loads of about 0.5 kgf,while more accurate hardness and fracture toughness values were obtained at intermediate and at higher indentation loads beyond 5 kgf respectively.A strong indentation size effect（ISE） was observed in both materials.The load independent hardness of SiC is 2563 HV,putting it far above the standard armor hardness requirement of 1500 HV that is barely met by ZTA.
Aleksandra Nastic1，Ali Merati2，Mariusz Bielawski2，Olaniyi Fakolujo1，Michel Nganbe1
1. Department of Mechanical Engineering,University of Ottawa2. National Research Council Canada
摘 要：Instrumented and Vickers indentation testing and microstructure analysis were used to investigate zirconia toughened alumina（ZTA） and silicon carbide（SiC）.Several equations were studied to relate the Vickers indentation hardness,Young’s modulus and crack behavior to the fracture toughness.The fracture in SiC is unstable and occurs primarily by cleavage leading to a relatively low toughness of 3 MPa m1/2,which may be inappropriate for multi-hit capability.ZTA absorbs energy by plastic deformation,pore collapse,crack deviation and crack bridging and exhibits time dependent creep.With a relatively high toughness around 6.6 MPa m1/2,ZTA is promising for multi-hit capability.The higher accuracy of mediar equations in calculating the indentation fracture toughness and the relatively high c/a ratios above 2.5suggest median type cracking for both SiC and ZTA.The Young’s modulus of both ceramics was most accurately measured at lower indentation loads of about 0.5 kgf,while more accurate hardness and fracture toughness values were obtained at intermediate and at higher indentation loads beyond 5 kgf respectively.A strong indentation size effect（ISE） was observed in both materials.The load independent hardness of SiC is 2563 HV,putting it far above the standard armor hardness requirement of 1500 HV that is barely met by ZTA.
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