ZA35-3.5Mn alloy was prepared by spray forming rapidly solidification technology.The thermo-stability of spray forming ZA35 alloy was studied by the heat exposure experiment.The principal test results show that the hardness of alloy increases by 2.3% than that of without heat exposure after heat exposure for 48h at 150 ℃;the second phase precipitation of MnZnAl3 and CuMnZn distributes evenly.After heat exposure for 120h at 150 ℃,hardness of alloy reduces by 26% and the strength increases slightly than that of without heat exposure.When the exposure temperature is higher than 200 ℃,the longer time of the heat exposure lasts,the lower hardness of the alloy is.After heat exposure for 120h at 200 ℃,the hardness of alloy reduces by 37%,the strength and elongation reduces significantly than that of without heat exposure.

Morphology and microstructure of over-sprayed powder in spray forming high Mn ZA35 alloy were observed by SEM(scanning electron microscope),and particle size in the powder was analyzed,and cooling rate of the powder was calculated,meanwhile,phase constituent in the alloy was analyzed by XRD(X-ray diffraction).The results indicate that with decreasing in size of the over-sprayed powder,the roundness of the power is increased.The average grain size of the powder prepared by atomization at 1.0MPa is refiner than that of one at 0.8MPa.The average cooling rate of the powder reaches 104～105 K/s.Microstructure of the ZA35 alloy containing high Mn is composed of α-Al phase with rich Mn element and η-Zn phase with rich Mn element.

The Zn-Al-Mn-Cu-Mg alloy was fabricated by using of spray forming process, and the effects of extrusion temperature on the microstructure and mechanical properties of alloy were investigated. The results show that when the extrusion temperature increased from 280°C to 320°C, the grain size coarsened with the precipitation of ZnAlMn 6 as Mn-riched compound, and the tensile strength and elongation decreased from 496.9 MPa and 5.31% to 441.2 MPa and 3.40%, respectively. But the hardness of alloy was not change significantly with the increasing of extrusion temperature. It is found that spray forming Zn-Al-Mn-Cu-Mg alloy has excellent mechanical properties at appropriate extrusion temperature of about 280°C.

In order to ensure the measurement precision,two Zernike moments operator with different masks was applied in dimension detecting of column deposit perform.The Zernike moments operator with mask of 3× 3 was used for detecting rapidly all probable edge points,while the Zernike moments operator with mask of 7×7 was used for relocating accurately edge.The detecting result shows that the thickness of the edge is one pixel,and the actual edge thickness is of the sub-pixel precision less than one.The saltation appeared in the edge of the image,which can not reflect the changing trend of the deposit preform,was restored using the Bezier curve.Thus,the perfect lineament of the column deposit perform was obtained.The proving result reveals that the relative dimension error of the deposit perform is 0.94%,which can satisfy the precise requirement of dimension detecting.

The ZA35 alloy with 3.5% Mn is manufactured with spray forming technique using the optimized parameters. The microstructure and corrosion resistance of casting and spray forming ZA35 alloy are studied. It is indicated that the microstructures of spray formed high Mn ZA35 alloy distribute homogeneous and the grains are refined. The element Mn exists mainly in the form of Mn-enriched independent hard phase in or near the interfaces of grains of casting ZA35 alloy, but the Mn-enriched independent hard phases are not found in spray formed high Mn ZA35 alloy. The solid solubility of Mn in ZA35 matrix is shifted to a higher level by spray forming. The corrosion trend of spray forming alloy with refined grain can be restrained considerably by the treatment of solid and aging.

Mechanical properties of ZA27 alloy obviously change under high mechanical pressure over 1 GPa. The metallographic microscope, hardness test and XRD were employed to reveal the changing rule of mechanical properties of ZA27 alloy under different pressures. The results show that the secondary dendrite arm spacing decreases while the yield strength and tensile strength increase with the reducing grain size, and compared with that under normal pressure, the hardness values under 1 GPa, 2 GPa, 3 GPa, 4 GPa and 5 GPa increased 13.1%, 30%, 39.1%, 52.1%, 64.9%, respectively.

High Mn-containing ZA35 alloy was prepared by spraying forming combining with hot squeezing casting at 320℃. Effects of varied squeezing ratios on microstructure and mechanical properties of the alloy were investigated. The results reveal that uniformly fine microstructure can be observed as a result of effectively restraining the precipitation of coarse Mn-rich phase in ZA-3.5Mn alloy during spraying forming. Subsequently,the as-deposited alloy can realize desirable compactness at a lower squeezing ratio during hot squeezing process,exhibiting excellent mechanical properties at room temperature.

采用喷射成形技术制备Mn含量为3.5%的ZA35合金,在不同温度和时间条件下研究了ZA35合金的时效特性.用X射线衍射、扫描和透射电镜等手段研究了合金的显微组织,并测定了合金的力学性能.结果表明,时效处理对喷射成形高锰ZA35合金力学性能影响明显.时效过程中,合金硬度随时间的延长出现了双峰现象.热力学稳定相MnAl6优先从过饱和的α-Al(η-Zn)中析出;随时效温度升高和时效时间延长,亚稳相Al11Cu5Mn3和CuMnZn6依次析出.时效析出的纳米级晶须状和颗粒状MnAl6显著提高了合金的力学性能,抗拉强度可达518 MPa,硬度为HB156,伸长率为9.85%.

利用定向凝固技术研究了生长速度和合金元素Cr对过共晶Al-Fe合金初生Al3Fe相生长过程的影响.结果表明:随着生长速度的增加.初生Al3Fe相将发生粗大板片状→厚片状→薄片状→分枝片状的转变.当加入合金元素Cr后,初生Al3Fe相的形貌由粗大板片状、厚片状、薄片状、分枝片状变成块状和片状.同时,讨论了各种形貌组织的形成机理.