| Laser direct rapid forming (LDRF) is a new and advanced solid fabrication technology which has been developed rapidly in the recent ten years. This technology integrates virtues of rapid prototyping and laser cladding technology, and can attain directly high performance and dense mental part without mould, with wider application foreground. It uses laser beam to melt metallic powder fed by co-axial nozzle layer by layer on a substrate, then a solid and functional component is produced. Comparing with traditional manufacturing method, it has some special advantages: short produce time, low produce cost, rapid response to market, component having excellent mechanical properties and graded function with variable composition and so on. It has been given more and more attention, as an advanced manufacturing technology having great potential. In this paper, LDRF is primary researched. The research mainly includes four parts:Firstly, we expound the technical principals, features of LDRF also its many problems in applying courses. Current states of development were summarized in china and other countries. The temperature field of moving point laser beam heat resource and convective mechanism in laser melt pool were presented.Secondly, the forming mechanism of LDRF were analyzed deeply. To create 3D hard mental parts by LDRF, a liquid phase sintering mechanism is applied. The material to be sintered consists of a mixture of two powder, a high-melting-point powder, called the structural powder, and a powder having a lower melting point, called the binder. The LDRF process involved several physical phenomena. These include: heat generation and transfer; microstructure evolution; fluid effects and mechanical issues. In these coexisting physical phenomena, the thermal problem is dominant.Thirdly, we have carried out LDRF experiments of DZ—Ni60AA powders by single-pass, multi-pass, multi-layer etc. Laser forming parameters have great impact...
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