International Journal of Microstructure and Materials Properties (6 papers in press)

Special Issue on: Novel Nanomaterials and Nanostructures

• Fatigue damage detection method of nano ceramic coating rail based on acoustic signal acquisition  
  by Zhinan Li, Yafei Li, Chenyou Li 
  Abstract: In order to reduce the fatigue damage detection error and improve the recall rate of fatigue damage data, this paper proposes a detection method based on acoustic signal acquisition for fatigue damage of nano ceramic coated rail. Firstly, the long-term fatigue behaviour of nano ceramic coated rail is analysed, and the typical damage evolution state of coating cracking at each stage is obtained; then, based on the ultrasonic theory, the one-dimensional nonlinear elastic wave equation of rail vibration signal propagation process is constructed, and the modulated sidelobe signal of high-frequency ultrasonic is obtained. Finally, modulation parameters of rail fatigue damage are calculated by Fourier transform to determine the extent of fatigue damage. Experiment shows that the maximum error of the method for fatigue damage detection is only 0.5 mm, and the damage recall rate can reach 99.9%, indicating that the method improves the detection effect for fatigue damage.
  Keywords: nano ceramic coating; rail; Fourier transform; acoustic signal; fatigue damage detection; ultrasonic theory; sidelobe signal.
  
  
• Preparation and electrical properties analysis of waterborne epoxy resin carbon nanotube composite materials  
  by Yan Sun, Xinjian Zhang, Li Niu 
  Abstract: Using multi-walled carbon nanotubes and waterborne epoxy resin as raw materials, a waterborne epoxy resin carbon nanotube composite material specimen was prepared. The effects of the amount of multi-walled carbon nanotubes and montmorillonite, as well as shear time, on the electrical properties of the composite material were analysed; analyse conductivity and dielectric loss through a broadband dielectric impedance spectrometer; use a high resistance meter to test surface and volume resistivity; analyse the mechanical and electrical performance through a universal testing machine combined with the four electrode method. The experimental results show that extending the stirring time can reduce the surface resistivity of composite materials and improve their conductivity; increasing the amount of multi-walled carbon nanotubes can reduce surface resistivity; increasing the amount of montmorillonite appropriately can improve the dielectric constant of the material.
  Keywords: waterborne epoxy resin; carbon nanotubes; preparation of composite materials; electrical performance analysis; conductivity; surface resistivity.
  
  
• An experimental study on mechanical properties of UV cured 3D nanofiber printing materials  
  by Hai Long, Shanjun Long 
  Abstract: To improve the mechanical properties of UV cured 3D printing materials after curing, this paper proposes a study on the mechanical properties of UV cured 3D nanofibre printing materials. By preparing THBP modified nano TiO2 as a subsequent auxiliary material, epoxy acrylate (EA) as a prepolymer, dipropylene glycol diacrylate (DPGDA) as a monomer, and phenyl bis (lithium phenyl-2,4,6-trimethylbenzoylphosphinate) phosphine oxide as a photoinitiator, a UV curable 3D printing material was prepared by adding THBP modified nano TiO2 in different proportions, and analyse the mechanical properties of the materials prepared by adding THBP modified nano TiO2 with different proportions of self synthesised THBP, in order to achieve the research of strengthening and toughening modification, and to improve its mechanical properties. The experimental results show that when the content of TEBP-TiO2 is 5 wt%, the tensile strength and impact strength of the samples prepared after UV curing reach the maximum value of 51.3 MPa and 22.1 KJ/m2, respectively. With the gradual increase of the content of THBP-TiO2, the initial decomposition temperature and the maximum decomposition temperature of the materials increase. The residual mass of thermal decomposition is increased and the thermal stability is improved.
  Keywords: UV curing; 3D printing; mechanical properties; nanofibres; THBP modification.
  
  
• The influence of carboxylated styrene butadiene lotion content on the microstructure of modified concrete  
  by Shuai Wang, Xinying Li 
  Abstract: In order to study the influence of carbobutadiene latex on the properties of concrete, this study studied the influence of carbobutadiene latex content on the microstructure of modified concrete. First of all, material selection and production of specimens, and then the physical properties, mechanical properties and microstructure of specimens were analysed to complete the effect of carboxybutene styrene latex content on the microstructure of modified concrete. The experimental results show that the modified concrete has better performance, minimum water reduction rate and higher bulk density when the content of carboxybutene styrene emulsion is 15%. By observing the microstructure, it is found that there are tree-trunk structure, latex film structure and interpenetrating network structure between latex film and concrete hydration products. At the same time, there are conical particles, which can greatly improve the performance of concrete.
  Keywords: carboxybutylbenzene; lotion content; modified concrete; microstructure.
  
  
• Optimisation method for durability of recycled concrete based on nano strengthening technology  
  by Xiaoyuan Xiong, Haixia Lu 
  Abstract: Studying the durability optimisation problem of recycled concrete can extend the service life of concrete structures and reduce maintenance costs. Therefore, the paper proposes a durability optimisation method for recycled concrete based on nano strengthening technology. Firstly, select experimental materials for recycled concrete, analyse the factors affecting the strength of recycled coarse aggregate concrete, and determine the design scheme of recycled concrete mix proportion; then, the recycled coarse aggregate was modified by soaking in nano SiO2 dispersion, and dispersed for 20 minutes using YM-060S ultrasonic dispersion machine before being placed in a container to optimise the durability of recycled concrete. The results show that the improved recycled concrete in this paper has increased its water resistance by more than 16% compared to RAC, and its quality loss rate does not exceed -0.21%, indicating that the method proposed in this paper can effectively improve the durability of recycled concrete.
  Keywords: nano strengthening; dispersion immersion method; frost resistance test; water penetration resistance test; concrete mix design.
  
  
• Study on low temperature discharge performance of lithium ion batteries for new energy vehicles  
  by Yiqing Chen, Youtong Li, Moyi Xie 
  Abstract: To explore the operating state of lithium-ion batteries for new energy vehicles at low temperatures, this study conducted a study on the low-temperature discharge performance of lithium-ion batteries for new energy vehicles. Firstly, the establishment of a low-temperature discharge test platform is completed using a battery charging and discharging test system, a host computer, and a thermal thermometer. Then, on the basis of the established platform, a low temperature environment is set up to test the performance of lithium-ion batteries. The results show that the lower the temperature, the lower the maximum available capacity and discharge capacity of the battery; At low temperatures, the battery can reach a thermal equilibrium state, but the accumulation of polarisation in the battery is more severe, which can easily lead to deterioration of its operating conditions. Therefore, operating at low temperatures is not recommended.
  Keywords: new energy vehicles; low temperature discharge performance test platform; near adiabatic working condition; natural convection conditions.