噴射沉積al11.3zn2.4mg1.1cu合金組織及性能研究

1、 （ 題 目 ：噴 射 沉 積 目 ：噴 射 沉 積 A l 11 . 3 Z n 2 . 4 M g 1 . 1 C u 合金 組 織 及 性 能 研 究合金 組 織 及 性 能 研 究 英 文 題 目 ： 英 文 題 目 ： Researches of Microstructues and Properties of Spray Deposited Al11.3Zn2.4Mg1.1Cu Alloy 研 究 生 ： 苑 彩 平

2、 研 究 生 ： 苑 彩 平 學(xué) 科 名 稱 ： 材 料 學(xué) 學(xué) 科 名 稱 ： 材 料 學(xué) 指 導(dǎo) 教 師 ： 白 樸 存 指 導(dǎo) 教 師 ： 白 樸 存 教 授 教 授 二 ○ ○ 七 年 五 月 二 ○ ○ 七 年 五 月 碩 士 學(xué) 位 論 文 碩 士 學(xué) 位 論 文 分類號:學(xué)校代碼: 10128 分類號:學(xué)校代碼: 10128 U D C :學(xué) 號: 20041165 學(xué) 號: 200411

3、65 Abstract The microstructure and mechanical properties of spray deposited Al11.3Zn2.4Mg1.1Cu alloy were investigated and analyzed by optical microscopy(OM), scanning electron microscopy(SEM), transmission electron micr

4、oscopy(TEM)，X-ray diffraction (XRD) and tensile test. Fracture mechanism and strengthened mechanism were discussed briefly in this paper. Microstructure observation showed that the as-deposited alloy was composed of equa

5、xial grains with the size of 20µm. after hotextrusion the alloy composed of fine-grain equiaxial grains, with typical size between 2 to 3µm. The optimal soild-solution technics of alloy was soluting 1.5 hour at

6、 480℃ and the optimal single-stage aging technics was aging 24 hour at 140℃. The tensile test results indicated that the strength of spray formed Al11.3Zn2.4Mg1.1Cu alloy was higher than that conventional casti

7、ng. After the single-stage aging technics of 480℃×1.5h＋140℃×24h the ultimate tensile strength of alloys could reach up to 849 MPa and the elongation being 3.3%. At the two-stage ageing technics of 480℃×1.5

8、h＋120℃×2h＋160℃×24h, the ultimate tensile strength of alloys was 716 MPa and the elongation being 6.3% The SEM, TEM and XRD investigated that the precipitate phases of single-stage aged alloy were GP(Ⅱ) zone, η

9、 ′ phase and L12-Al3Zr particles. The strengthening mechanisms were fine-grain strengthening, soild-solution strengthening and precipitation strengthening, so with high strengthen of alloy. The SEM morphologies demonstra

10、ted that the fracture mechanisms of alloy were intergranular fracture and transgranular fracture, but the intergranular fracture was more and have micro-crack in alloy, so the plasticity of alloy was low. The precipitate

11、 phases of two-stage aged alloy was η phase, the strengthen of experimental alloy reduced and the SEM morphologies demonstrated that the main fracture mechanisms were intergranular fracture and transgranular fracture,an