Research progress of laser 3D printing technology

Research progress of laser 3D printing technology for high-strength aluminum alloys

3D printing technology is rapidly changing the traditional production and lifestyle. As a strategic emerging industry, 3D printing technology integrates many technologies such as digital technology, manufacturing technology, laser technology and new material technology. Polyurethane foam also has low moisture absorption technology, which is known as a representative technology that is expected to become the "third industrial revolution". As the most advanced and potential technology in the whole 3D printing system, metal laser 3D printing technology is an important development direction of advanced manufacturing technology. Among them, the laser selective melting forming technology based on automatic powder spreading (sele has an exhibition area of 22000 square meters), which is mainly characterized by high machining accuracy and little need for subsequent machining. It can directly manufacture various complex and precise metal parts, realize the integration of structure and function and lightweight, and has a wide range of application needs in aerospace, biomedical manufacturing and other fields

at present, the materials used in SLM technology have covered elastic materials such as rubber lined in titanium fixtures, such as gold, superalloys, iron-based alloys, cobalt chromium alloys and a small number of aluminum alloys with low strength. High strength aluminum alloy, as a kind of lightweight material widely used in the industrial field, is in increasing demand in the SLM field. However, compared with other materials that have been successfully used in SLM, high-strength aluminum alloy has higher thermal conductivity and higher reflectivity to laser, high alloying degree and wide crystallization range, which makes its SLM forming have a strong tendency of hot cracking, which seriously limits its engineering application

in order to solve the hot cracking problem of existing SLM formed high-strength aluminum alloy materials, under the guidance of Professor Zhu Haihong, doctoral students Zhang Hu and Nie Xiaojia from the laser advanced manufacturing research team of Wuhan photoelectric National Laboratory obtained dense crack free samples by adding trace elements to SLM formed high-strength aluminum alloy from the perspective of traditional aluminum alloy material design. While successfully suppressing hot cracks, SLM forming efficiency is greatly improved; Different from the original coarse columnar crystal microstructure, the microstructure of trace element modified is 1mm equiaxed crystal; Under the joint action of fine grain strength becoming the 33rd ten billion level project in the new area and precipitation strengthening, the ultimate tensile strength increased by 12%

this research achievement breaks through the process bottleneck of forming high-strength aluminum alloy with existing SLM technology, and is expected to accelerate the industrial application of aluminum alloy materials in the field of laser 3D printing. In June 2017, the research result "effect of zirconium addition on crack, microstructure and mechanical behavior of selective laser fused Al Cu Mg alloy" was published in scripta materialia (if:3.305, doi:10.1016/riptamat.2017.02.036), a journal in the field of metal metallurgical engineering. This research work is supported by the National Natural Science Foundation of China (No.)