Surface hardness distribution effects upon contact, gap and joint conductances

Author(s):  
M. YOVANOVICH ◽  
A. HEGAZY ◽  
J. DEVAAL
Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 812
Author(s):  
Mihály Réger ◽  
Richárd Horváth ◽  
Attila Széll ◽  
Tamás Réti ◽  
Viktor Gonda ◽  
...  

The aim of this study is to exhibit the mutual connection between surface and in depth hardness values in the case of surface-treated metal samples with inhomogeneous hardness distribution in the surface layer. The reason for surface treatments of metal alloys is most commonly to increase the hardness and wear resistance at the surface. Case depth, as a result of surface treatment and the in-depth hardness distribution, can be determined by measuring the hardness of a section perpendicular to the treated surface and by metallographic examination. The result of heat treatment can also be checked rapidly by surface hardness testing. Surface hardness carries only indirect information regarding case depth and hardness distribution. Surface and cross-sectional hardness can be related to the mathematical modeling of the plastic zone developing in the indentation process. The mathematical model applied in this study allows the conversion of the surface hardness function into the in-depth hardness function and vice-versa. The calculation method presented was validated by analyzing the hardness data of nitrocarburized samples of various case depths. The validation result proves that cross-sectional hardness distribution can be adequately estimated by surface hardness data in the case of a surface layer with monotonically decreasing hardness distribution.


2018 ◽  
Vol 25 (01) ◽  
pp. 1850040 ◽  
Author(s):  
SIYUAN WU ◽  
SHOUJUN WU ◽  
GUOYUN ZHANG ◽  
WEIGUO ZHANG

In the present work, hardness and elastic modulus of a titanium nitride coatings prepared on Ti6Al4V by powder immersion reaction-assisted coating (PIRAC) are tested and comparatively studied with a physical vapor deposition (PVD) TiN coating. Surface hardness of the PIRAC coatings is about 11[Formula: see text]GPa, much lower than that of PVD coating of 22[Formula: see text]GPa. The hardness distribution profile from surface to substrate of the PVD coatings is steeply decreased from [Formula: see text]22[Formula: see text]GPa to [Formula: see text]4.5[Formula: see text]GPa of the Ti6Al4V substrate. The PIRAC coatings show a gradually decreasing hardness distribution profile. Elastic modulus of the PVD coating is about 426[Formula: see text]GPa. The PIRAC coatings show adjustable elastic modulus. Elastic modulus of the PIRAC coatings prepared at 750[Formula: see text]C for 24[Formula: see text]h and that at 800[Formula: see text]C for 8[Formula: see text]h is about 234 and 293[Formula: see text]GPa, respectively.


1989 ◽  
Vol 15 (3) ◽  
pp. 343-359 ◽  
Author(s):  
G S Leonard ◽  
G D Tovey ◽  
M E Aulton

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.


2019 ◽  
Vol 64 (11) ◽  
pp. 1007-1014
Author(s):  
Tong XU ◽  
◽  
Jia-Hui ZHANG ◽  
Zhao-Ying LIU ◽  
Xuan LI ◽  
...  

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.


Alloy Digest ◽  
2011 ◽  
Vol 60 (12) ◽  

Abstract Dillidur 450V is a water hardened wear-resistant steel with surface hardness at room temperature of 420-480 HB. The steel is easy to weld and bend. Hot working is not recommended. This datasheet provides information on composition, physical properties, hardness, tensile properties, and bend strength as well as fracture toughness. It also includes information on wear resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-638. Producer or source: Dillinger Hütte GTS.


Alloy Digest ◽  
2017 ◽  
Vol 66 (12) ◽  

Abstract NITRODUR 8524 (8CrMo16, 1.8524) is one of the Nitrodur family of nitriding steels that are used where high surface hardness and good fatigue strength are required and the material is also subjected to high temperatures. Nitrided surfaces maintain their hardness and strength at operating temperatures of up to approximately 500–550 deg C (932–1022 deg F). This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as casting and forming. Filing Code: SA-807. Producer or source: Schmolz + Bickenbach Group.


Alloy Digest ◽  
1994 ◽  
Vol 43 (4) ◽  

Abstract LUKENS HARDWEAR 500 is a premium abrasion resistant alloy steel with improved forming and welding characteristics. Typical surface hardness range (BHN) of 477-520, depending on thickness. This datasheet provides information on composition and hardness. It also includes information on forming and joining. Filing Code: SA-472. Producer or source: Lukens Steel Company.


Alloy Digest ◽  
1994 ◽  
Vol 43 (3) ◽  

Abstract LUKENS HARDWEAR 425 is a premium abrasion resistant alloy steel with improved forming and welding characteristics. Typical surface hardness range (BHN) is 400-444, depending on thickness. This datasheet provides information on composition and hardness. It also includes information on forming and joining. Filing Code: SA-471. Producer or source: Lukens Steel Company.


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