本文選題：鋯鉻合金 + 熱變形��； 參考：《燕山大學》2015年碩士論文

【摘要】：Zr及Zr合金具有熱中子吸收截面積小,密度小,優(yōu)異的抗腐蝕、抗氧化和耐輻照等理化性能,主要應用在核工業(yè)。隨著研究人員對Zr合金的進一步研究,發(fā)現(xiàn)其作為結構材料有很廣泛的應用前景。Zr合金四種常見的組織中兼具強度和塑性的組織為等軸組織和雙態(tài)組織。基于此,本文以Zr-Cr二元合金為研究對象,通過成分優(yōu)化、熱變形和熱處理工藝使合金組織發(fā)生再結晶,獲得雙態(tài)組織或等軸組織,同時提高合金的強度和塑性。實驗設計了一系列不同成分的ZrCr合金,通過真空非自耗電弧熔煉爐制備出合金錠,研究了合金成分對其組織和性能的影響。結果表明,少量的Cr添加到純Zr中就能大幅度提高合金的強度。合金的強度隨Cr含量的增加而增加,而塑性隨合金中Cr含量的增加而降低。當Cr含量為1.8 at%時,合金具有較高的強度,抗拉強度為1058MPa,同時延伸率能達到9.6%。Cr含量繼續(xù)增加到3 at%時,抗拉強度增加到1232MPa,延伸率為6.2%。根據(jù)實驗分析,選定1.8 at%Cr合金做固溶時效和退火處理,研究其微觀組織和力學性能之間的演變關系。實驗發(fā)現(xiàn),經900℃固溶水冷后,合金形成了等軸組織,抗拉強度和塑性較熱軋態(tài)的都有提升,分別為1109MPa和11.0%。合金在隨后的時效過程中,隨時效溫度的增加,合金的強度下降,塑性有了大幅度提升。合金在700℃,塑性達到了最好,延伸率為18.4%,強度還保持在818MPa。合金時效過程中強度下降的原因是固溶體α相中Cr含量的急劇下降,合金的畸變降低。退火后的合金強度下降,塑性得到了提升。當退火溫度高于800℃時,合金開始發(fā)生部分再結晶,900℃合金的組織已完全為等軸狀組織。
[Abstract]:Zr and Zr alloys are mainly used in nuclear industry because of their small thermal neutron absorption cross section, low density, excellent corrosion resistance, oxidation resistance and radiation resistance. With the further study of Zr alloy, it is found that Zr alloy is widely used as structural material. Among the four common microstructures of Zr alloy, the structures with both strength and plasticity are equiaxed and bi-state. Based on this, the Zr-Cr binary alloy was studied in this paper. The microstructure of Zr-Cr binary alloy was recrystallized by optimization of composition, hot deformation and heat treatment, and the double structure or equiaxed structure was obtained, and the strength and plasticity of the alloy were improved at the same time. A series of ZrCr alloys with different compositions were designed experimentally. Alloy ingots were prepared by vacuum non-consumable arc melting furnace. The effect of alloy composition on the microstructure and properties of ZrCr alloy was studied. The results show that the strength of the alloy can be greatly improved by adding a small amount of Cr to pure Zr. The strength of the alloy increases with the increase of Cr content, while the plasticity decreases with the increase of Cr content in the alloy. When Cr content is 1.8 at%, the tensile strength of the alloy is 1058 MPA, and the tensile strength increases to 1232 MPA and the elongation reaches 6.2 MPA when the content of Cr continues to increase to 3 at%. According to the experimental analysis, 1.8atCr alloy was selected for solution aging and annealing, and the evolutionary relationship between microstructure and mechanical properties was studied. It was found that the alloy formed equiaxed structure after water cooling at 900 鈩，

本文編號：2023503