本文選題：Sb + Mg-2.7Nd-0.4Zn-0.5Zr合金�。� 參考：《哈爾濱理工大學》2015年碩士論文

【摘要】：耐熱鎂合金一般都是稀土含量較高的稀土鎂合金，它們在汽車制造業(yè)、國防工業(yè)、航空、航天等領域有著廣闊的應用前景。Mg-Nd-Zn-Zr鎂合金是“Mg-RE-Zr系”鑄造鎂合金的一種。該合金是以釹為主要合金元素的高強耐熱鎂合金，，鑄造性能良好，顯微疏松傾向和壁厚敏感性低，室溫和高溫性能優(yōu)異。目前對該系合金的研究主要集中在稀土元素（如Nd、Y、Ce、La等）、Zn以及擠壓制備工藝等對該系合金組織和性能的影響；本文首次提出以高強度耐熱鎂合金Mg-2.7Nd-0.4Zn-0.5Zr為基礎，通過添加Sb微合金化和新的熱處理工藝，探究元素Sb對Mg-2.7Nd-0.4Zn-0.5Zr鎂合金顯微組織結構和力學性能的影響。 本文通過X射線物相分析(XRD)、光學顯微鏡(OM)、掃描電子顯微鏡(SEM)、EDS能譜分析、透射電子顯微鏡(TEM)、硬度測試以及室溫拉伸試驗等分析手段，系統(tǒng)地研究了微量Sb的變化對Mg-2.7Nd-0.4Zn-0.5Zr-xSb合金組織和力學性能的影響，揭示了元素Sb對合金材料的強化機制。實驗結果表明，在含Zr鎂合金中加入微量的合金元素Sb，由于生成Mg3Sb2相，可以對Mg-2.7Nd-0.4Zn-0.5Zr-xSb合金產(chǎn)生以下影響：進一步顯著細化鑄態(tài)、固溶態(tài)、時效態(tài)合金材料的晶粒尺寸，抑制合金材料晶粒長大；改善了鑄態(tài)合金離異共晶相Mg12Nd的形貌、大小和分布；明顯提高鑄態(tài)、固溶態(tài)、時效態(tài)合金材料的硬度、強度和塑性。在不同熱處理狀態(tài)下，隨著合金元素Sb含量的增加，晶粒變得更加細小，硬度基本上呈現(xiàn)持續(xù)增加的趨勢，強度和塑性先增加后減��；基本上所有性能均在0.08wt%Sb附近達到極大值，不同熱處理狀態(tài)下合金材料的最小平均晶粒尺寸分別為13.9um（鑄態(tài)）、35.7um（固溶態(tài)）和37.1um（時效態(tài)），最高布氏硬度分別為67.7（鑄態(tài)）、65.1（固溶態(tài)）和89.5（時效態(tài)），最大抗拉強度分別為184MPa（鑄態(tài)）、198MPa（固溶態(tài)）和275MPa（時效態(tài)），最大屈服強度分別為117MPa（鑄態(tài)）、112.7MPa（固溶態(tài)）和205.5MPa（時效態(tài)），最大斷后伸長率分別為11.1%（鑄態(tài)）、23.5%（固溶態(tài)）和9.1%（時效態(tài)），最大斷面收縮率分別為11.2%（鑄態(tài)）、20.1%（固溶態(tài)）和9.5%（時效態(tài)）。元素Sb對鎂合金的強化效果主要是由于細晶強化機制引起的。 元素Sb對合金材料斷裂方式影響較小，合金材料的斷裂方式分別主要為沿晶斷裂（鑄態(tài)）、穿晶準解理斷裂（固溶態(tài)）和穿晶解理斷裂（時效態(tài)）。 綜合本文試驗結果，Mg-2.7Nd-0.4Zn-0.5Zr合金加入0.08wt%Sb為宜。
[Abstract]:Heat-resistant magnesium alloys are generally rare earth magnesium alloys with high rare earth content. They have broad application prospects in automobile manufacturing industry, national defense industry, aviation, aerospace and other fields. Mg-Nd-Zn-Zr magnesium alloy is one of the casting magnesium alloys of "Mg-RE-Zr series". The alloy is a high strength and heat resistant magnesium alloy with neodymium as the main alloy element. It has good casting properties, low susceptibility to microporosity and wall thickness, and excellent properties at room and high temperature. At present, the study of the alloy mainly focuses on the effect of rare earth elements (such as Ndndyyyyralum cerium La and so on) on the microstructure and properties of the alloy, which is based on the high strength and heat resistant magnesium alloy Mg-2.7Nd-0.4Zn-0.5Zr for the first time. The effect of SB on microstructure and mechanical properties of Mg-2.7Nd-0.4Zn-0.5Zr magnesium alloy was investigated by adding SB microalloying and new heat treatment process. In this paper, X-ray phase analysis (XRDX), optical microscope (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), hardness test and room temperature tensile test are used to analyze the structure of the alloy. The effect of the change of trace SB on the microstructure and mechanical properties of Mg-2.7Nd-0.4Zn-0.5Zr-xSb alloy was systematically studied, and the strengthening mechanism of the element SB on the alloy material was revealed. The experimental results show that the addition of trace alloy element SB to Zr-containing magnesium alloy can have the following effects on Mg-2.7Nd-0.4Zn-0.5Zr-xSb alloy due to the formation of Mg3Sb2 phase: further, the grain size of as-cast, solid solution and aged alloy materials can be significantly refined. The morphology, size and distribution of Mg12Nd were improved, and the hardness, strength and plasticity of as-cast, solid solution and aged alloy materials were obviously increased. Under different heat treatment conditions, with the increase of SB content, the grain size becomes smaller and the hardness increases continuously, the strength and plasticity increase first and then decrease, and almost all the properties reach the maximum near 0.08wt%Sb. The minimum average grain sizes of alloy materials under different heat treatment conditions are 13.9um (as cast) and 37.1um (aged), respectively. The highest Brinell hardness is 67.7 (as cast, 65.1 (solid solution) and 89.5 (aged), respectively, and the maximum tensile strength is respectively. The maximum yield strength is 117MPa (as-cast 112.7MPa (solid solution) and 205.5MPa (aged 205.5 MPa), respectively. The maximum elongation after break is 11.1mm (solid solution) and 9.1 (aging), respectively. It is 11.2U (as cast) and 9.5A (aged). The strengthening effect of element SB on magnesium alloy is mainly caused by fine grain strengthening mechanism. Element SB has little effect on the fracture mode of alloy materials. The fracture modes of alloy materials are mainly intergranular fracture (as cast), transgranular quasi-cleavage fracture (solid solution state) and transgranular cleavage fracture (aging state). The results show that Mg-2.7Nd-0.4Zn-0.5Zr alloy is suitable for adding 0.08wt%Sb.
【學位授予單位】：哈爾濱理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG146.22

【參考文獻】

相關期刊論文 前6條

1 楊忠,李建平,常見虎,王海軍,朱小彬,張康虎,余申衛(wèi),曹玉泉;銻和混合稀土對AZ91鎂合金流動性的影響[J];熱加工工藝;2004年05期

2 郭敬潔;劉新田;;添加混合稀土和銻的AZ31鎂合金的熱變形和加工圖[J];熱加工工藝;2007年05期

3 王梅;劉建睿;沈淑娟;黃衛(wèi)東;;銻對AZ91D鎂合金微觀組織的影響[J];熱加工工藝(鑄鍛版);2006年03期

4 楊景紅,田素貴,于興福,張祿廷,孫根榮,金敬鉉;微量元素Sb對AZ31合金組織與蠕變性能的影響[J];沈陽工業(yè)大學學報;2005年03期

5 汪正保,劉靜,袁澤喜;Sb對鎂合金組織和力學性能的影響[J];特種鑄造及有色合金;2005年09期

6 黃伯杰,聶邦盛,賈延杰,吳雅琴;Mg-Nd-Zn-Zr耐熱高強鑄造鎂合金[J];特種鑄造及有色合金;1998年06期

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