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In this paper, we investigated the effects of building orientation and heat treatment temperature on the anisotropy of SLM-formed AlSi10Mg specimens. Three different deposition orientations of 0°, 45° and 90° and heat treatment temperatures of 270 °C, 300 °C and 330 °C were used to hold the specimens for 2 h, followed by furnace cooling. The metallographic organization, fracture morphology, grain size and morphology, grain orientation and distribution were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). SEM metallographic shows that the white cell structure is eutectic Si where Si grid-like structure distributes around α-Al dendrites. EBSD results show that all specimens consist of a large number of grains growing along direction, which is the preferred orientation. The organizational changes in grain size, distribution and low-angle grain boundaries (LAGBS) caused by orientation and heat treatment were analyzed to confirm the anisotropy of the SLMed AlSi10Mg alloy and to analyze and explain the reasons for the poor plasticity of the 90° orientation. The present results provide new insights into the effects of deposition direction and heat treatment parameters on the microstructure and properties of AlSi10Mg alloy prepared by SLM.

Since former president Obama of America put forward the concept of 3D printing or additive manufacturing, it had been putting into use rapidly and getting acceptance widely. In particular, metal additive manufacturing machines had been successfully applied with pilot demonstration in industry. However, the present metal additive manufacturing machines cannot be directly used in medical fields such as dental restoration because of some different requirements between industry and medical fields. In this case, this paper is aimed for the development of laser fusion printing machine (LFP), also being called as selective laser melting (SLM), for ceramic teeth crown in dental restoration business. Through the reasonable design and development of key components such as machinery unit, optical unit, electrical controlling unit, and software unit, and the integration, debugging, and optimization of the entire system, the laser fusion printing apparatus for dental restoration has been successfully developed. Key technologies such as machine structure design, optical unit design, electrical controlling system design, system software and process software have been overcome, on the basis of which, a lot of process experiments of medical titanium alloy materials were deeply carried out. At last laser fusion printing technology of titanium alloy was mastered, and titanium dental crown by laser fusion printing with relative density up to 97.37% was realized. After post treatment with porcelain, it was found that the laser fusion printed porcelain teeth with titanium alloy has good metal-ceramic bonding strength, which is equivalent to the quality of traditional porcelain teeth, which showed that laser fusion printing can meet the requirements of dental restoration business and has a broad market outlook.

Selective laser melting (SLM) additive manufacturing technology has been a prevailing method to fabricate components with complex physical geometry or novel structural design. However, original nuclear powder material such as vanadium-based alloy appropriate for SLM processing has yet not been obtained commercially, which significantly restricts the development of nuclear component manufacturing. In this study, near-sphere, uniform and fine V-6Cr-6Ti pre-alloy powder which met the performance demands for SLM processing was successfully obtained by high-energy ball milling. Subsequently, the V-6Cr-6Ti part was fabricated by SLM consolidation of as-prepared pre-alloy powder with double-region orthometric scanning strategy, forming strong texture feature within molten pool. The compression test was performed, showing that the maximum compression stress reached 1078 MPa and the accumulated strain was about 0.32.

As an application of the equations to degraded nuclear plant piping subjected to large dynaminc loading, the plastic response of a cracked cantilever beam or pipe is studied.