PRODUCTION OF HIGH FRACTURE TOUGHNESS AND HIGH FATIGUE STRENGTH BULK METALLIC GLASSES AND EXAMINATION OF THE MECHANISM

高断裂韧性和高疲劳强度大块金属玻璃的制备及机理检验

基本信息

批准号：
14350063
负责人：
FUJITA Kazutaka
金额：
$ 8.96万
依托单位：
Ube National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Single phase (SF) bulk glassy alloys (BGAs) and nanocrystalline (NC) EGAs of some Zr-, Cu- and Pd-based systems have been synthesized by some fabrication methods. Where, the NC BGA is the glassy alloy which contain nano-scale crystalline particles embedded homogeneously in glassy matrix. Then fatigue strength and fracture toughness in these BGAs were examined.The ratio of fatigue limit (σ_w ; half a full stress amplitude) under stress ratio of 0.1 to tensile strength (σ_B) of the Zr-based NC BGA showed a value of 15% (σ_B=1.7 GPa), and it was approximately three times larger compared with the ratio of the SF BGA of the same composition. The ratio of σ_w to σ_B of the Cu-based BGA exhibited a very large value of 24% (σ_B=2.0 GPa). These σ_w s show the enough values for applications. It is thought that the drastic rise in the σ_w of these NC BGAs is derived from the prevention of slip initiation and propagation by the NC particles.A Zr-based BGA with a high degree of amorphousness exhibited a fracture touness value (Kic) of 53 MPa・m^<1/2>. It was clarified that the Zr-based BGA has a sufficient Kic for practical uses. The Kic s of a Zr-based NC BGA and considerably crystallized Zr-based BGA were small even in the maximum value with 40 and 11 MPa・m^<1/2>, respectively. This is thought to be due to the embrittlement by the crystallization.The Pd-based SF BGA could not have fatigue cracks, and the value of notched fracture toughness exhibit 36 MPa・m^<1/2> and cracks propagated in three or more directions at the same time. An estimated K/c showed a small value of 12 MPa・m^<1/2>.

某些Zr-，Cu-和Pd的系统的单相（SF）散装玻璃合金（BGA）和纳米晶（NC）EGA已通过某些制造方法合成。在哪里，NC BGA是玻璃合金，其中含有纳米级的结晶颗粒，将均匀嵌入玻璃基质中嵌入。然后检查了这些BGA中的疲劳强度和断裂韧性。在应力比为0.1与抗拉力强度（σ_b）的疲劳极限（σ_W;一半完全应激振幅）的比率比BGA的组合比例大约为15％（σ_b= 1.7 gpa），其值为15％（σ_b= 1.7 gpa），它的组合均大约为SF。基于Cu的BGA的σ_W与σ_b的比率非常大24％（σ_b= 2.0 GPA）。这些σ_ws显示了足够的应用值。人们认为，这些NC BGA的σ_W的急剧上升源自NC颗粒的防滑启动和传播。基于ZR的BGA具有高度无定形的BGA，表现出53 MPA的断裂Touness值（KIC）为53 MPA ・MPA ・M^m^<1/2>。可以澄清的是，基于ZR的BGA具有足够的KIC用于实际用途。基于ZR的NC BGA的KIC和基于ZR的BGA的KIC s也很小，即使在最大值中分别为40 mpa和11 MPa ・M^<1/2>。这被认为是由于结晶的益处。基于PD的SF BGA无法具有疲劳裂纹，而缺口断裂韧性的价值暴露于36 MPA ・MPA ・M^<1/2>，并且在三个或更多的方向上裂纹在三个或更多方向传播。估计的K/C的值为12 MPa ・M^<1/2>。