Kefeng Li's research while affiliated with Guangdong Academy of Agricultural Sciences and other places

... Many recent studies have focused on processing new phases and materials from elementally mixed powders using different techniques. Parts having multiphase structures were obtained in these studies [14][15][16][17][18]. ...

... Although high-performance composites with high-density and uniformly dispersed reinforcing phases can be achieved by an in-situ synthesis method, it remains a challenging technical issue to fully control in-situ reactions considering the non-equilibrium metallurgical process of LPBF [14][15][16][17][18]. Laser processing parameters and starting material constituents are normally used to tailor the in-situ reactions in LPBF. ...

... Nanocrystalline soft magnetic materials are generally obtained by annealing amorphous soft magnetic materials at an appropriate temperature. The annealing process also has an effective effect on the soft magnetic properties of nanocrystalline materials [11,12]. Zhao et al. [13] systematically studied effects of the annealing temperature on the B s and H c of FeSiBCuNbP nanocrystalline powders and the µ e and P cv of the corresponding NSMCs. ...

... The melt-spin ribbons are generally wound into toroidal magnetic cores, but difficult to produce complex shapes. Jia Xu et al. reported that the toroidal cores was wounded use amorphous ribbons, the effective permeability value decreased from 2.0 9 10 5 to 2.0 9 10 4 sharply [17]. With the increase of application frequency, the ribbons often crushed into flaky powders, and made into magnetic cores by molding. ...

... The well-studied equiatomic or near-equiatomic shape memory NiTinol alloys are not dimensionally stable, as their austenite-martensite phase transformation temperatures are around room temperatures and show a relatively low hardness value (~30 HRC), making them unsuitable for structural applications [8,[10][11][12]. On the contrary, the combination of dimensional stability, a high hardness that is comparable to bearing steels, and other advantageous properties of 60NiTi make this Ni-rich grade of NiTi alloys a suitable candidate for structural applications [8,[13][14][15][16]. As an example, this alloy is a good candidate to be employed as a rolling element bearing material that is highly corrosion resistant and endures high levels of shock loads before experiencing any permanent deformation, and also for lubricated sliding applications [17][18][19][20]. ...

... However, contrasting results on the effectiveness of HIP have been reported. For instance, Shi et al. demonstrated simultaneous improvement of tensile strength and ductility in the LB-PBF 17-4 PH steels upon HIP [31]. In contrast, Burns et al. report that tensile ductility of alloy with high initial porosity did not improve even with the application of higher HIP pressure [5]. ...

... Because of the property of shape memory, nitinol implants retain their morphology even under large pressure and deformation. Today nitinol is used for wires of orthodontic tooth alignment [38]. Other usages of nitinol are vena cava filters, osteosynthesis staples, and other vascular applications. ...

... However, the research work conducted on 3D printing of very Ni-rich grades of NiTi alloys, such as 58NiTi, 60NiTi, etc., with dense microstructures is not substantial. In a recent study, Khanlari et al. [36] printed parts from a Ni-rich Ni-Ti powder mixture, consisting of about 63 wt.% Ni and 37 wt.% Ti, by using a laser powder bed fusion technique (LPBF). ...

... 4 Scanning Figure 5 demonstrates the relationship between yield strength (σ 0:2 ) and mean β grain size (D β ) for all tested TixFZ alloys. According to Hall-Petch relationship, the σ 0:2 decreases with an increase in the D β of a material, the Hall-Petch relationship satisfies for all the TixFZ alloys, i.e., the σ 0:2 increases as the D β decreases [29,30]. The Ti25FZ alloy demonstrates the highest σ 0:2 , i.e., 1043 ± 20 ...

... Layer-by-layer melting of powder layers of 20-60 µm makes it possible to achieve cooling rates up to 10 6-8 K/s and this circumstance is an excellent opportunity to use SLM for producing BMGs of complex geometric configuration. However, it is very difficult to obtain defect-free Fe-based material structure without any defects via SLM due to extremely high levels of internal stresses and technological features of the process [16][17][18][19][20][21][22][23]. There are different ways that scientists are using to improve the selective laser melted amorphous and nanocrystalline samples quality, such as optimal process parameters selection and application of multi-scanning strategies with different patterns. ...