Tracking the information about your manuscript
Communicate with the editorial office
Query manuscript payment status Edit officeCollecting, editing, reviewing and other affairs offices
Managing manuscripts
Managing author information and external review Expert Information Expert officeOnline Review
Online Communication with the Editorial Department
Downloads
Page Views
Information
Journal Title: Modern Transportation and Metallurgical Materials
Established: July 2021
Governing Authority: Jiangsu Association for Science and Technology
Sponsors: Jiangsu Provincial Comprehensive Transportation Society
Jiangsu Provincial Society for Metals
Publication Frequency: Bimonthly
Tel: 025-58783287
Email: xdjtyyjcl@163.com
CN 32-1895/TF
ISSN 2097-017X
Influence mechanism of gypsum hydration phases on the shrinkage of metallurgical by-product-based low-carbon cementitious materials
JIN Yanji;ZHOU Yang;HONG Jinxiang;MIAO Changwen;Supersulfated cement(SSC) combines low clinker content with strong engineering adaptability, making it suitable for pavement grouting, void backfilling, and rapid repair of bridge and slabtrack systems. To clarify the influence of desulfurization gypsum hydration phase on SSC, two systems with otherwise identical mix parameters were designed, that is, hemihydrate gypsum(SDG) and dihydrate gypsum(TDG). The initial setting time, volumetric stability(autogenous and drying shrinkage), and compressive strength are compared, and the hydration products and microstructure are characterized. The results show that SDG exhibits a markedly shorter initial setting(～15 min), whereas TDG sets after >6 h. In deformation, SDG presents early autogenous contraction followed by a transient expansion, and an analogous early rebound in drying shrinkage. TDG displays monotonic contraction, with both autogenous and drying shrinkage significantly larger than SDG. At identical binder proportions, SDG achieves higher compressive strength at all ages(28-day strength of 10 SDG: 36.7 MPa). Phase and microstructural analyses indicate greater AFt formation and a denser micro-network in SDG. Overall, the hemihydrate phase is better aligned with rapid setting and shrinkage control for fasttrack repairs, while the dihydrate phase is preferable when a longer working window is required.
The effect of pulsed magnetic field and La addition on the as-cast microstructure of Cu-Ni-Si alloy
CHEN Shuaifeng;LIU Tianyu;LI Yinghuan;WANG Songwei;LUO Tianjiao;SONG Hongwu;Cu-Ni-Si alloy is a key candidate material for integrated circuit lead frames, owing to its combined advantages of high strength and high electrical conductivity. Its microstructure directly dictates the material's performance. The influence of pulsed magnetic field on the as-cast macrostructure and microstructure of Cu-Ni-Si and Cu-Ni-Si-La alloys is systematically investigated via optical metallography, scanning electron microscopy, and other characterization techniques. The results indicate that under conventional solidification conditions, the grains of Cu-Ni-Si alloy are predominantly columnar and coarsely distributed. In contrast, after the application of pulsed magnetic field, a transition from columnar grains to equiaxed grains is observed, with the proportion of columnar grains reduced by 28.7% and the grains significantly refined. When La element and pulsed magnetic field act synergistically, the proportion of columnar grains increases to 67.7%. Nevertheless, the size of equiaxed grains at the center region is relatively uniform, which is finer compared to that under conventional solidification. Additionally, circular hollow phases composed of Ni, Si, and La are formed.
Wall thickness uniformity in three-roll planetary rolling of copper tubes: a multi-source measurement approach
SUN Yingjie;LIANG Haicheng;LIU Jinsong;SUN Yao;CAI Ling;CHEN Dayong;LIU Hongkou;The wall thickness uniformity of copper tubes produced by three-roll planetary rolling is a critical factor determining their final quality. To investigate the distribution characteristics of wall thickness, this study conducts a comparative analysis using a multi-method approach combining finite element simulation, ultrasonic testing equipment, and high-density manual measurements on TP2 copper tubes. The finite element simulation results reveal the presence of significant stress inhomogeneity and non-uniform metal flow during the rolling process. Experimental measurements further confirm that the wall thickness exhibits pronounced periodic fluctuations along both the axial and helical directions. Fourier transform and spectrum analysis identify dominant fluctuation wavelengths of 113.4 mm(online ultrasonic testing), 113.6 mm(offline ultrasonic testing), 125.4 mm(manual axial measurement), and 113.6 mm(manual helical measurement), respectively. These identified wavelengths are significantly larger than the theoretical rolling pitch calculated based on the revolution period of the rolls. This key finding indicates that the primary cause of wall thickness non-uniformity is not inherent to the planetary rolling process itself, but is more likely attributable to the dynamic characteristics of the equipment, such as medium-to-low frequency mechanical vibrations in the feeding system. By cross-validating multi-source data, this study accurately reveals the dominant periodic characteristics affecting wall thickness uniformity, providing a clear theoretical basis for improving product quality from the perspective of equipment stability control.
Analysis of the causes of diagonal defects on the inner wall of TP2 inner-grooved copper tubes
LIANG Haicheng;SUN Yao;LIU Jinsong;SUN Yingjie;CHEN Dayong;LIU Kun;JIANG Liping;Stereomicroscopy, metallographic microscopy, and scanning electron microscopy(SEM) are employed to address the issue of diagonal streaks on the inner wall of TP2 inner-grooved copper tubes. The study includes the analysis of the morphology of the diagonal defects and the morphology and composition of the grooved mandrel. Additionally, stress analysis is used to investigate the formation mechanism of the inner wall diagonal streaks, and measures to prevent and control the occurrence of such defects are proposed. The results indicate that the diagonal defects on the inner wall of the inner-grooved copper tubes are actually composed of numerous grooves and pits. This is attributed to the presence of pits on the tooth crest of the grooved mandrel, which increases the resistance of the copper material flowing into the bottom grooves of the mandrel during the rolling process. This results in a lack of material near the root of the inner groove, macroscopically manifesting as diagonal streaks on the inner wall. Improving the wear resistance and hardness of the grooved mandrel, along with enhancing the lubrication effectiveness, can prevent and control the formation of diagonal streaks on the inner wall of inner-grooved copper tubes.
News
