Development of Damage-Tolerant and Fracture-Resistant Materials by Utilizing the Material Inhomogeneity Effect

2019 ◽  
Vol 86 (11) ◽  
Author(s):  
O. Kolednik ◽  
R. Kasberger ◽  
M. Sistaninia ◽  
J. Predan ◽  
M. Kegl
Keyword(s):  
High Strength ◽  
Crack Arrest ◽  
Basic Mechanism ◽  
Hot Press ◽  
Crack Driving Force ◽  
Material Inhomogeneity ◽  
Interface Delamination ◽  
Press Bonding ◽  
Damage Tolerant ◽  
Force Concept

Abstract The improvement of fracture strength by insertion of thin, soft interlayers is a strategy observed in biological materials such as deep-see sponges. The basic mechanism is a reduction of the crack driving force due to the spatial variation of yield strength and/or Young's modulus. The application of this “material inhomogeneity effect” is demonstrated in this paper. The effectiveness of various interlayer configurations is investigated by numerical simulations under application of the configurational force concept. Laminated composites, made of high-strength tool steels as matrix materials and low-strength deep-drawing steel as interlayer material, were manufactured by hot press bonding. The number of interlayers and the interlayer thickness were varied. Fracture mechanics experiments show crack arrest in the first interlayer and significant improvements in fracture toughness, even without the occurrence of other toughening mechanisms, such as interface delamination. The application of the material inhomogeneity effect for different types of matrix materials is discussed.

scholarly journals Investigation on the physical properties and diffusion layer phase transformation at the interface of Sialon-Duplex Stainless-Steel bonding

2021 ◽  
Vol 15 (3) ◽  
pp. 8450-8458
Author(s):  
Mohamed Ahmed Rady ◽  
Patthi Hussain ◽  
Nagoor Basha Shaik ◽  
Balaji Bakthavatchalam
Keyword(s):  
Stainless Steel ◽  
Phase Transformation ◽  
Physical Properties ◽  
Duplex Stainless Steel ◽  
Diffusion Layer ◽  
Diffusion Bonding ◽  
Research Work ◽  
Hot Press ◽  
Press Bonding ◽  
And Diffusion

Joining SiALON to duplex stainless steel utilizes the properties of two materials which may provide an opportunity for distinctive applications. Ceramic is hard and operates at a high temperature but it is brittle whereas metal is tough but it can work at a low temperature. The benefits of the best properties of both materials can be utilized by joining them. The objectives of the research work are to investigate the physical properties and the phase transformation at the interface and at the inter-diffusion layer in between the SiAlON and duplex stainless steel. The experiment incorporated nitriding, then diffusion bonding the duplex stainless steel using the hot press. Bonding was carried out at 1200°C for the holding times of 30 minutes and 1 hour.  Metallography and micro analyses were conducted to achieve the above objectives. The study has demonstrated that 30 minutes joining time is sufficient to develop the thickness of the interface. However, 1 hour joining duration achieved cohesive and sound diffusion bonding of the SiAlON to duplex stainless steel. This is possible due to the formation of diffusion interlayer which accommodates the residual stress presence during cooling down process.

Fabrication of Al/Ni Multilayer Composite by Electrodeposition and Hot Press Bonding and Investigation of its Bending Property

2019 ◽  
Vol 793 ◽  
pp. 3-8
Author(s):  
Ming Zhi Wang ◽  
Liang Sheng Qiu ◽  
Liang Hu Cheng ◽  
Xiang Liu ◽  
Jian Shao ◽  
...  
Keyword(s):  
Bending Strength ◽  
Bending Test ◽  
Multilayer Composite ◽  
Hot Press ◽  
Exothermic Reactions ◽  
Bending Property ◽  
Bonding Condition ◽  
Evolution Phase ◽  
Press Bonding ◽  
Dc Current

The Al/Ni multilayer composite with highly exothermic reactions and good plasticity was fabricated by electrodeposition and hot press bonding process. The Al/Ni multilayer composite consisted of the microscale Al and Ni layers. The Ni layers were electroplated on Al foils for a certain time and DC current, and then a mounts of deposited foils were stacked and combined as a whole bulk Al/Ni multilayer composite. In this study, the microstructure evolution, phase transformation, exothermic heat and bending property of the Al/Ni multilayer composite during various hot press bonding were studied by SEM, XRD, DSC and bending test. Under the hot press bonding condition of 400°C and 1h, the exothermic heat, the bending strength and the bending displacement reached 916J/g, 614.5MPa and 4mm, respectively. The results showed that by the increasing time of hot press bonding, the bending displacement of the Al/Ni multilayer composite improved firstly and then declined sharply. It was also found that when the time of hot press bonding increased, the bending strength and the exothermic heat decreased simultaneously, owing to the nucleation and growth of the Al3Ni phases in the interfaces between Al and Ni layers.

Modeling of Solid-State Hot Press Bonding and Its Application to the Fabrication of Titanium Alloy Joints

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
C. Zhang ◽  
H. Li ◽  
M. Q. Li
Keyword(s):  
Solid State ◽  
Diffusion Mechanism ◽  
Three Dimensional ◽  
Main Step ◽  
Flow Mechanism ◽  
Hot Press ◽  
Surface Source ◽  
Void Closure ◽  
Macroscopic Deformation ◽  
Press Bonding

Solid-state hot press bonding is an advanced joining process wherein two specimens can be joined under high pressure for a period of time at an elevated temperature. The main step in hot press bonding is the void closure process. In the present study, a three-dimensional theoretical model for describing the void closure process is developed. In the model, the void closure process is divided into two stages: in the first stage, surface asperities are flattened by the time-independent local plastic flow mechanism, and isolated voids form at the bonding interface; in the second stage, the void closure is accomplished by three time-dependent mechanisms, namely, the viscoplastic flow mechanism, surface source diffusion mechanism, and interface source diffusion mechanism. The initial and ending conditions of these mechanisms are proposed. The model also includes an analysis of the effect of macroscopic deformation on void closure. Hot press bonding experiments of Ti–6Al–4V alloy are conducted to validate the model. The modeling predictions show good agreement with the experimental results.

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