In Situ Synthesis and Characterization of Zr-Based Amorphous Composite by Laser Direct Deposition

Abstract

Zr-based bulk metallic glasses have attracted extensive interest for structural applications due to their excellent glass-forming ability, superior mechanical properties, and unique thermal and corrosion properties. In this study, Zr 65 Al 10 Ni 10 Cu 15 amorphous composites with a large fraction of amorphous phase were in situ synthesized by laser direct deposition. X-ray diffraction confirmed the existence of both amorphous and crystalline phases. Laser parameters were optimized in order to increase the fraction of amorphous phase. The microstructure analysis by scanning electron microscopy revealed the deposited structure was composed of periodically repeated amorphous and crystalline phases. Overlapping regions with nanoparticles aggregated were crystallized by laser reheating and remelting processes during subsequent laser scans. Vickers microhardness of the amorphous region showed around 35 pct higher than that of crystalline region. Average hardness obtained by a Rockwell macrohardness tester was very close to the microhardness of the amorphous region. The compression test showed that the fracture strain of Zr 65 Al 10 Ni 10 Cu 15 amorphous composites was enhanced from less than 2 pct to as high as 5.7 pct, compared with fully amorphous metallic glass. Differential scanning calorimetry test results further revealed the amorphous structure and glass transition temperature T g was observed to be around 660 K (387°C). In 3 mol/L NaCl solution, laser direct deposited amorphous composites exhibited distinctly improved corrosion resistance, compared with fully crystallized samples.

Biomedical materials and techniques to improve the tribological, mechanical and biomedical properties of orthopedic implants – A review article

“…Although the fracture strain can be improved from 2% to 5.5% regarding to the existence of crystalline phase within the amorphous matrix, it is still need more investigation [54]. In addition, the production processes are expensive as it requires high purity elements and expensive consumables [36] 4.…”

Additive Manufacturing of Advanced Multi‐Component Alloys: Bulk Metallic Glasses and High Entropy Alloys

“…[108] The successful fabrication of crackfree Zr-based BMG specimens was mainly attributed to a low thermal stress generated in the SLM process while the high toughness of Zr-based BMG may also play a role in suppression of micro-crack formation. [111] However, up till now, the fabrication of crack-free Fe-based BMGs have not been achieved and more work needs to be done to fine-tune the processing parameters to eliminate the cracks. [109,110] The formation of intermetallic and the residual stresses caused by the different coefficient of thermal expansion (CTE) might contribute to the crack formation in the laser-foil-printing of Zr-based BMG onto a Ti substrate ( Figure 3).…”

“…[4,84,103,111,117,118] Their mechanical properties have also been investigated and reported in several studies. [4,84,103,111,117,118] Their mechanical properties have also been investigated and reported in several studies.…”

“…[84] However, in this study, Zr-based BMG showed very little ductility or no ductility at all. [108] The mechanical properties of laser direct deposited Zr-based BMGs were investigated by Ye et al [111] Although the compressive strength of the laser deposited Zr-based BMGs was similar to the Zr-based BMGs fabricated by arc melting, it showed a significantly improved ductility with a strain around 5.5%, much higher than the arc melted Zr-based BMG which is around 2%. [108] It was also reported that the SLMed Zr-based BMG composites showed a low Young's modulus, which was mainly attributed to the defects in the SLMed BMG samples.…”

“…[84] In a similar study conducted by Ouyang et al, the fabricated Zr-based BMG composites samples using SLM also showed a similar strength to their counterparts fabricated by cast and again only little ductility was observed ( Figure 10). [111] The wear properties of a laser direct deposited Fe-based metallic glass composite was investigated by Ye et al [106] The wear mechanism was primarily adhesive because only a small amount of wear debris was generated. [108] Interestingly, the fractural angle of the SLMed BMGs was around 90 , totally different from the conventional cast Zr-based BMGs which had a fractural angle around 42 .…”