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Development of high strength aluminum alloy sheet by powder rolling-spark sintering technique using rapidly solidified powder

快速凝固粉末粉末滚压-火花烧结技术开发高强度铝合金板材

基本信息

批准号：
10450274
负责人：
YANAGISA Osamu
金额：
$ 3.07万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450274/
关键词：
powder rolling, spark sintering rapidly solidified powder aluminum alloys 放電焼結圧延

项目摘要

The sintering of aluminum materials is difficult, since their affinity for oxygen is very high and their temperature range for sintering is very narrow. The advantage of spark sintering is summarized as follows : (1)The dielectric breakdown of the oxide film is caused between the powder particle surfaces, (2)The sintering process is finished under the condition of the shorter low temperature exposure. In order to develop the high strength aluminum sheet, the technique, (hereafter called powder rolling-spark sintering process), having both process of powder rolling and spark sintering for fabrication of metallic sheet is used for cold rolling and spark sintering of 7075-rapidly solidified aluminum powder in this study. The obtained results are summarized as follows :1. Only surface temperature of materials can be measured by radiation pyrometer (non-contact infrared thermometer with laser beam targeting) in the powder rolling-spark sintering process. However, the inner temperatures of m … More aterials is important in the sintering process. The real temperatures of graphite punches and compacts are measured by using of thermo couples in the die-press style spark sintering machine. The relation between temperature of materials-surface and one materials-center is obtained from these measurements.2. The various microstructures is obtained by changing of process parameters, such as holding temperature, period of sintering and cooling method. The microstructural changes is investigated using TEM and x-ray diffraction techniques. The solid soluted amount of main alloying elements increases as the holding temperature and period increase, which results in substitution of both homoginizing and solution heat treatments.3. The behavior of age-hardening is same for materials sintered at 873K for 10 to 2400 sec. On the other hand, plastic strain of material increases as the holding period in the sintering at 873K increases, and that of materials sintered at 873K for 1200sec is same as that of solution treated materials. It is suggested on the basis of value of the plastic strain obtained from tensile test that materials sintered under the conditions of the long exposure and higher temperatures show largely solid-soluted amount of main alloying elements and promotion of sintering.4. The computer soft for solidification analysis is modifed for spark sintering process. The thermal analysis including current-, voltage-change and heat generation process is carried out. Less

铝材料的烧结是困难的，因为它们对氧的亲和力非常高，并且它们的烧结温度范围非常窄。电火花烧结的优点是：（1）在粉末颗粒表面之间形成氧化膜的介电击穿;（2）烧结过程在较短的低温暴露条件下完成。为了开发高强度铝板，本研究采用粉末轧制-电火花烧结工艺，对7075快速凝固铝粉进行冷轧和电火花烧结。主要研究结果如下：1.在粉末轧制-放电烧结过程中，辐射高温计（激光瞄准的非接触式红外测温仪）只能测量材料的表面温度。然而，m的内部温度 ...更多信息材料在烧结过程中很重要。在模压式电火花烧结机上用热电偶测量了石墨冲头和压坯的真实的温度。得到了材料表面温度与材料中心温度的关系.通过改变保温温度、烧结时间和冷却方式等工艺参数，获得了不同的显微组织。使用TEM和X射线衍射技术的微观结构的变化进行了研究。主要合金元素的固溶量随保温温度和保温时间的增加而增加，导致均质化和固溶热处理的替代.在873 K下烧结10 ~ 2400秒的材料时效硬化行为相同。在873 K保温1200秒后，材料的塑性应变随保温时间的增加而增加，且与固溶处理后的塑性应变基本相同。根据拉伸试验得到的塑性应变值，认为在长时间暴露和较高温度条件下烧结的材料，主要合金元素的固溶量较大，促进了烧结.针对电火花烧结工艺，对计算机凝固分析软件进行了改进。进行了热分析，包括电流、电压变化和发热过程。少