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Improvement of Toughness at Cryogenic Temperature by Structure Controlling in Al-Zn-Mg Alloys

通过结构控制提高 Al-Zn-Mg 合金的低温韧性

基本信息

批准号：
05650674
负责人：
SAJI Shigeoki
金额：
$ 1.41万
依托单位：
Toyama University (1994)Osaka University (1993)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650674/
关键词：
Al-Zn-Mg alloys Structure controlling Lamellar structure Cryogenic Temperature Temperature Dependence Work done for tensile fracture 3 point bend test Fracture toughness AL-Zn-Mg系合金靭性の改善強度引張試験

项目摘要

Three different Al-4.5%Zn-1%Mg alloys ; alloy No.1 with no addition of chromium, titanium and zirconium, alloy No.2 with 0.2%Cr and 0.06%Ti and alloy No.3 with 0.2%Cr, 0.06%Ti and 0.1%Zr were prepared. Ingots obtained were homogenized at 470ﾟC for 8 hours and then hot-rolled under different conditions to give different microstructures. Alloy No.1 showed aspect ratio of crystal grains about 4, alloy No.2 showed aspect ratio of about 9, and alloy No.3 aspect ratio of above 160. The hot plates were solution-treated at 450ﾟC for2 hours, water-quenched and aged at 120ﾟC to peak-age conditions. The rod shape of tensile specimens and specimens for 3 point bend test were cut from the aged final plates. Tensile test was carried out at the various temperatures between 7 to 293K.3 point bend test was carried out at 4.2,20-23,77.4 and 293K.Proof stress, tensile strength, uniform elongation, work done for tensile fracture increase with decreasing temperature to about 20K and decrease gradually with temperature for the three alloys. Data of ductility and toughness at cryogenic temperatures of Al-Zn-Mg alloys are novel and very important. Temperature dependence of fracture toughness K_Q and R_<Sb> correspond to the uniform elongation and work done for tensile fracture. High ductility and toughness are obtained in order of alloy No.3, No.1 and No.2. Alloy No.3 with the typical lamellar structure, aspect ratio above 160, showed the highest ductility and toughness and the lowest strength. Alloy No.1 with aspect ratio of about 4 showed higher ductility and toughness than alloy No.2 with aspect ratio of about 9. Thus, correspondence with ductility or toughness and the degree of lamellar structure is not so strong.

三种不同的Al-4.5%Zn-1%Mg合金；制备了不添加铬、钛和锆的合金No.1、含有0.2％Cr和0.06％Ti的合金No.2以及含有0.2％Cr、0.06％Ti和0.1％Zr的合金No.3。获得的铸锭在470℃下均化8小时，然后在不同条件下热轧以得到不同的显微组织。合金No.1的晶粒长宽比约为4，合金No.2的长宽比约为9，合金No.3的长宽比大于160。热板在450℃下固溶处理2小时，水淬并在120℃下时效至峰值时效条件。从老化的最终板材上切下拉伸试样和三点弯曲试验的棒状试样。在7至293K的不同温度下进行拉伸试验。在4.2、20-23、77.4和293K进行3点弯曲试验。三种合金的屈服强度、抗拉强度、均匀伸长率、拉伸断裂功随温度降低至20K左右而增加，并随温度逐渐降低。 Al-Zn-Mg 合金低温下的延展性和韧性数据是新颖且非常重要的。断裂韧性 K_Q 和 R_<Sb> 的温度依赖性对应于均匀伸长率和拉伸断裂所做的功。按照合金No.3、No.1、No.2的顺序获得了高延展性和韧性。 3号合金具有典型的片状结构，长宽比在160以上，塑性和韧性最高，强度最低。长径比约为4的合金No.1表现出比长径比约为9的合金No.2更高的延展性和韧性。因此，延展性或韧性与层状结构程度的对应性不那么强。