行波磁场铸造zl205a合金薄壁件的组织和性能分析word格式论文.docxVIP

AbstractIn this paper, continuous casting was simulat ed and the basic parameters was established in order to obtain thin- walled cylindrical castings of aluminum-copperalloy, the influence of different parameters on microstructure、properties and macro-defects of ZL205A alloy was researched under traveling magnetic field on vertical pouring system.By using two different casting molds to conduct the experiment . The resultsshowed that the former extended the effect time of magnetic field, casting defects can be removed when the induced current reached 10A.The microstructure of ZL205A under cast and T6 heat treatment states was observed, and tested room- temperature tensile, respectively. The variation of variousperformance indicators( σb、σ0.2 and δ) have been got.Under traveling magnetic field, the grain s were refined obviously. The grain size decreased continuously with increasing the in duced current , when the induced current reached 20A , the grain size is about 1/3 of the non-magnetic alloy grain, but when the induced current reached 25A, the micro-shrinkage increased. According to the Hall- Petch formula, yield strength σb showed a linear relationship with the reciprocal of the square root of grain diameter d-1 /2 , then the variation of the cast ZL205A alloy mechanical properties with the induced current(A) was researched, the properties of ZL205A firstly increases and then decreases with the increases of the induced current . When the induced current was 20A, σb(m ax ) is 221MPa, when itis 15A, σ0.2 (m ax ) is 105MPa, δ(m ax ) is 13.8%, increased by 11% 、 17% and 18%respectively, compared with non-magnetic alloy, the fracture showed the characteristic of the intergranular fracture. Horizontal contrast found that the central position of the thin- walled cast showed the best properties.Based on the above-mentioned ZL205A thin-walled cylindrical casts, selected the central positon to conduct the same T6 heat treatment pr