Recently, the Chinese Mechanical Engineering Society announced the selection results of 2023 Excellent Scientific and Technological Papers. After online evaluation by review experts and on-site evaluation by a final review expert committee composed of 21 experts, the Chinese Mechanical Engineering Society has selected 2023 Excellent Scientific and Technological Papers, including 9 review papers, 34 basic research papers, and 65 applied research papers. The selection results were published on the official website of the Chinese Mechanical Engineering Society. One paper from the Foundry journal was selected, and four papers from China Foundry journal were selected.

Congratulations to all the authors awarded the "Excellent Scientific and Technological Papers"!

Thanks to all the editorial board members, reviewers, and authors for their strong support to these two journals over the years!  I would like to thank the readers for their attention and citation to our journals.

Thanks to the State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology and National Joint Engineering Research Center of High Performance Metal Wear Resistant Materials Technology, Jinan University for their strong support!

The five Excellent Scientific and Technological Papers are:

1. Effect of HEA/Al composite interlayer on microstructure and mechanical property of Ti/Mg bimetal composite by solid-liquid compound casting (Vol. 20 No. 1, 2023)

Jin Cheng, Jian-hua Zhao, Chun Wang, Jing-jing Shangguan, Cheng Gu, Ya-jun Wang

DOI: https://doi.org/10.1007/s41230-022-2105-z

Abstract: In this study, HEA/Al composite interlayer was used to fabricate Ti/Mg bimetal composites by solid-liquid compound casting process. The Al layer was prepared on the surface of TC4 alloy by hot dipping, and the FeCoNiCr HEA layer was prepared by magnetron sputtering onto the Al layer. The influence of the HEA layer thickness and pouring temperature on interface evolution was investigated based on SEM observation and thermodynamic analysis. Results indicate that the sluggish diffusion effect of HEA can effectively inhibit the interfacial diffusion between Al and Mg, which is conducive to the formation of solid solution, especially when the thickness of HEA is 800 nm. With the increase of casting temperature from 720 °C to 730 °C, 740 °C, and 750 °C, α-Al(Mg), α-Al(Mg)+Al3Mg2, Al3Mg2+Al12Mg17, and Al12Mg17+δ-Mg are formed at the interface of Ti/Mg bimetal, respectively. When the thickness of the HEA layer is 800 nm and the pouring temperature is 720 °C, the bonding strength of the Ti/Mg bimetal can reach the maximum of 93.6 MPa.

2. Precipitation and evolution of nodular graphite during solidification process of ductile iron (Vol. 17 No. 4, 2020)

Jin-hai Liu, Jian-shuai Yan, Xue-bo Zhao, Bin-guo Fu, Hai-tao Xue, Gui-xian Zhang, Peng-hui Yang

DOI: https://doi.org/10.1007/s41230-020-0042-2

Abstract: The quantity and morphology of spheroidal graphite have an important effect on the properties of ductile iron, and the characteristics of spheroidal graphite are determined by the solidification process. The aim of this work is to explore the precipitation and evolution of graphite nodules in hypoeutectic, eutectic, and hypereutectic ductile irons by thermal analysis, liquid quenching and metallographic technique. Results show that hypoeutectic ductile iron has the longest solidification time and the lowest eutectic temperature; eutectic ductile iron has the shortest solidification time; hypereutectic ductile iron has the highest eutectic temperature. After solidification is completed, hypoeutectic ductile iron has the lowest nodule count, nodularity and graphite fraction; eutectic ductile iron has the highest nodule count, nodularity and the smallest nodule diameter; hypereutectic has the highest nodule diameter and graphite fraction. The nucleation and growth of graphite nodules in hypereutectic ductile iron starts before bulk eutectic crystallization stage, however, the precipitation and evolution of graphite nodules of hypoeutectic and eutectic ductile irons mainly occur in the eutectic crystallization stage. The graphite precipitated in eutectic crystallization of hypoeutectic, eutectic, and hypereutectic ductile irons, are 61%, 68% and 43% of total graphite volume fraction, respectively. Simultaneously, there are plenty of austenite dendrites in hypoeutectic and hypereutectic ductile irons, which are prone to shrinkage defects. Therefore, the eutectic ductile iron has the smallest shrinkage tendency.

3. Grain refinement of primary silicon in hypereutectic Al-Si alloys by different P-containing compounds (Vol. 18 No. 1, 2021)

Benson Kihono Njuguna, Jia-yan Li, YiTan, Qian-qian Sun, Peng-ting Li

DOI: https://doi.org/10.1007/s41230-021-0074-2

Abstract: The grain refinement behavior of Si-3P, Si-25Mn-10P, and Al-10Si-2Fe-3P master alloys on hypereutectic Al-24Si alloy was studied. Microstructure analysis indicates that the P-containing compounds in the three master alloys are SiP, MnP, and AlP, respectively. The coarse flower-like primary silicon in the Al-24Si alloy transforms into smaller, well-distributed blocks with the addition of various master alloys. When pouring at 840 °C, the average grain size of the primary silicon refined by Si-25Mn-10P master alloy with a holding time of 30 min is about 18 µm, which is significantly smaller than those refined by Si-3P and Al-10Si-2Fe-3P master alloys. The grain size shows an increasing trend when the holding time is further prolonged. Higher holding temperature has a positive effect on the grain refinement of Si-25Mn-10P master alloy. The grain refinement mechanism of the three master alloys was also discussed.

4. Finite element analysis for die casting parameters in high-pressure die casting process (Vol. 16 No. 4, 2019)

Xin-yu Qin, Yong Su, Jian Chen, Lan-jun Liu

DOI: https://doi.org/10.1007/s41230-019-8088-8

Abstract: The gating system and the overflow system were designed according to the casting structure during high pressure die casting (HPDC) process. The simulation was carried out by ProCAST software to visualize the injection chamber pre-crystallization and the flow of molten metal. The main work is to research four die casting process parameters, i.e. injection temperature, low-pressure velocity, high- and low-pressure velocity’s switching position, and high-pressure velocity. Experimental results show that the higher injection temperature and low-pressure velocity can mitigate the pre-crystallization of the injection chamber. However, when the low-pressure velocity exceeds 0.2 m·s⁻¹, the air entrapment in the chamber occurs. Besides, when the high-pressure velocity is greater than 2.5 m·s⁻¹, the overflow channel at the final filling position is covered by the liquid metal too early. Finally, the injection temperature of 650 °C, the low-pressure velocity of 0.2 m·s⁻¹, the high- and low-pressure velocity's switching position of 320 mm and the high-pressure velocity of 2 m·s⁻¹ are obtained as the optimal parameters by the software simulation, which has been verified by actual production.

5. Effect of Al-TCB on Grain Refinement and Mechanical Properties of ZL205A Alloy (Vol. 71 No. 11, 2022) (In Chinese)

Yan Xi-rui, Han Meng-xia, Lin Han, Hu Kai-qi, Liu Gui-liang, Liu Xiang-fa

Abstract: Al-TiCB master alloy (Al-TCB), containing B doped TiC_x particles, was applied to ZL205A alloy containing Zr melt by casting process, and the effects of the Al-TiCB master alloys on the microstructures and properties of ZL205A alloy were studied. The phases of the Al-TCB master alloy, the microstructure, the fluidity and mechanical properties of ZL205A alloys were analyzed and tested respectively by using of optical microscope, thermal field scanning electron microscopy, electron probe micro-analysis methods. The results show that the α-Al grains in ZL205A are significantly refined, the average grain sizes are refined from 236.8 μm to 77.7 μm, 75.5 μm, 69.2 μm after adding 0.5wt.%, 1.0wt.%, 2.0wt.% Al-TCB, respectively. The grain refining effect is stable, the resistance to 'Zr-poisoning' is strong, and there is no obvious phenomenon of refinement decline. Adding 4.0wt.% Al-TCB can reach the grain refinement limit, at this time the grain size is 63.9 μm. The morphologies of the α-Al grains change from dendrite to nearly spherical. Moreover, the fluidity of ZL205A melt is significantly improved after adding 1.0% of the Al-TCB, the length of the fluidity sample is increased from 457 mm to 644 mm which is increased by 40.9%. The yield strength, tensile strength and elongation of ZL205A are 430 MPa, 493 MPa and 9.7% after adding 1.0% of the Al-TCB, which are increased by 3.6%, 3.1% and 70.1% respectively.