Ti基非晶的玻璃形成能力及其内生复合材料

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	Ti基非晶的玻璃形成能力及其内生复合材料
	唐明强
学位类型	博士
导师	胡壮麒 ; 张海峰
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料学
关键词	金属玻璃 Ti基非晶合金复合材料内生剪切带 Metallic Glass Ti-based Amorphous Alloy Composite In-situ Shear Band
摘要	"Ti基金属玻璃具有高的比强度，优异的抗腐蚀性能，是一种具有应用前景的新型材料。但是Ti基金属玻璃的形成能力较弱，并且室温载荷作用下的塑性有限，大都表现为脆断。为满足应用需求，发展具有高玻璃形成能力的，并兼有良好塑韧性的新型Ti基非晶合金具有重要意义。本工作以Ti-Zr-Ni-Cu-Be五元合金系为基础，在相图富Ti区系统地研究了合金的玻璃形成能力，内生韧性增强相Ti基金属玻璃复合材料的形成、力学性能。主要结论如下：本文在Ti-Zr-Ni-Cu-Be体系中的(Ti33.4Zr24.4)-(Ni4.4Cu8.4)-Be伪成分三角形中，通过比较合金热力学特征和凝固组织，在富Ti区重点研究两个区域A和B。其中A区是玻璃易形成区域，该区域具有最佳玻璃形成能力的合金是Ti33.4Zr24.4Ni4.4Cu8.4Be29.4，水淬条件下，其形成金属玻璃的临界尺寸是直径22mm。B区为内生韧性增强相金属玻璃复合材料易形成区域，其中Ti45.7Zr33.0Ni3.0Cu5.8Be12.5（记作ZT-M合金）合金的非晶基体Ti32.8Zr30.2Ni5.3Cu9Be22.7（记作ZT3合金）合金的玻璃形成能力较高。水淬条件下，其形成金属玻璃的临界尺寸大于直径50mm。对该合金的各项测试结果表明：Ti32.8Zr30.2Ni5.3Cu9Be22.7的力学性能优异，压缩和拉伸断裂强度分别为1831MPa和1765MPa，密度为5.541g·cm-3。 Cu的增减能够有规律性地影响 (Ti36.1Zr33.2Ni5.8Be24.9)100-xCux合金的玻璃形成能力。当x介于0~3时，合金玻璃形成能力较低，100g纽扣锭中发现大量Be2Zr和Ni10Zr7晶态相。当x介于5~17时（ZT系列合金），合金玻璃形成能力随Cu含量增加逐渐下降。ZT1，ZT2和ZT3（x分别为5, 7, 9）合金形成金属玻璃的临界尺寸介于直径50mm~60mm之间。用Fe和Co完全替换Ni能够提高ZT3合金的玻璃形成能力，替换后合金具有3%以上的压缩塑性变形能力。替换后的ZTF3和ZTC3合金虽然玻璃形成能力有所提高，但晶化激活能下降，合金抗晶化能力和热稳定性下降。内生枝晶复合材料ZT-M合金具有高的两相结构稳定性。无论是高冷速的甩带样品还是低冷速的铜模浇铸Φ15mm棒材均能保持析出单一β-Ti相，而体心立方结构β-Ti相的形成依赖于剩余液相。ZT-M合金具有5%以上的拉伸塑性，加工硬化明显；当枝晶相体积分数一定时，复合材料屈服强度保持一定，析出相尺寸增加，材料塑性变形能力提高。采用直接调控增塑相摩尔百分数的方法成功制备了系列含有β-Ti相的(Ti32.8Zr30.2Ni5.3Cu9Be22.7)100-x(Ti61.5Zr36.4Cu2.1)x(x=10~95)非晶复合材料。随x值增加，枝晶体积分数增加。压缩载荷作用下，内生枝晶相的体积分数与力学性能之间存在非单调关系，只有超过临界值后（为36%），才能改善合金的塑性，且体积分数越高，塑性改善效果越明显，加工硬化明显。"
其他摘要	"Ti-based bulk metallic glasses (BMGs) have many attractive properties such as high specific strength and excellent corrosion resistance. However, the glass forming ability (GFA) of Ti-based BMGs is limited, exhibiting very little macroscopic plastic deformation and brittle fracture at room temperature. It is of great industrial applications to develop new Ti-based BMGs with high GFA and excellent mechanical properties. In this work, based on Ti-Zr-Ni-Cu-Be quinary alloys, the GFA, forming characteristics and mechanical properties for a series of Ti-based metallic glass and their composites were investigated. In the (Ti33.4Zr24.4)-(Ni4.4Cu8.4)-Be pseudo-composition triangle, the region A and B were researched mainly by comparing the thermodynamic characteristics of alloys in Ti rich region. In region A, the alloys are more apt to form bulk metallic glass. The best BMGs forming compositions in region A is Ti33.4Zr24.4Ni4.4Cu8.4Be29.4. Its critical diameter for forming metallic glass is 22mm by water-quenched method. In region B, the alloys are more apt to form in-situ composites. The matrix nominal composition of Ti45.7Zr33.0Ni3.0Cu5.8Be12.5 (denoted as ZT-M alloy) composite is Ti32.8Zr30.2Ni5.3Cu9Be22.7 (denoted as ZT3 alloy). The critical diameter for forming metallic glass of ZT3 is 50mm by water-quenched technique. Ti32.8Zr30.2Ni5.3Cu9Be22.7 exhibits better properties. The compression and tensile fracture strength are 1831MPa and 1765MPa, respectively, and the density is 5.541g·cm-3. The GFA of (Ti36.1Zr33.2Ni5.8Be24.9)100-xCux has been studied. When x=0~3, massive Be2Zr and Ni10Zr7 phases are found in the pancake with the mass of 100g, and their GFA is decreased. When x =5~17(ZT series alloys), with increasing the content of Cu, the GFA of ZT alloys is gradually decreased. The critical diameters for forming metallic glass of ZT1, ZT2 and ZT3(x=5, 7, 9, respectively) alloys are between 50mm and 60mm. The GFA and plastic deformation ability (plastic strain > 3%) of ZT3 are both improved by completely substituting Ni with Fe or Co. However, the thermal stability decreases. The in-situ composite ZT-M owns high structural stability. Only β-Ti crystalline phase forms in the ribbon and the as-cast rod with a diameter of 15mm. The β-Ti phase with the body-centred cubic structure depends on the residual liquid. The tensile plastic strain of ZT-M is over 5%. When the dendrite volume fraction maintains a certain amount, the yield strength of ZT-M alloy does not change. The plastic deformation ability of ZT-M improves with the dendrite size increasing. A series of (Ti32.8Zr30.2Ni5.3Cu9Be22.7)100-x(Ti61.5Zr36.4Cu2.1)x(x=10~95, in atomic percentage) bulk amorphous alloy composites with quantitatively controlled in-situ formation of bcc-dendrites were prepared. With the increasing x, the volume fraction of dendrites rises monotonically. Compression tests show that the volume fraction of dendrites largely influences the mechanical properties of the composites. When the volume fraction is lower than the critical value (approximately 36%), the plasticity of composites cannot be improved. When the volume fraction is over the critical value, the higher the volume fraction of dendrites, the larger the plastic strain and the stronger the work hardening capacity."
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64466
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	唐明强. Ti基非晶的玻璃形成能力及其内生复合材料[D]. 北京. 中国科学院金属研究所,2012.