钛-20钒-4铝-1锡合金性质分析

鈦-20釩- 4鋁- 1錫合金性質分析

The Properties of Ti-20V-4Al-1Sn Alloy

研究生：常傳賢 C. H. Chang

指導教授：趙志燁 C. Y. Chao

【摘要】

由於鈦合金具有良好的抗蝕性與優異的比強度，因此被廣泛應用於高爾夫球頭產業，最典型材料為雙相6-4鈦合金。近來，由於高的比強度需求，故目前高爾夫球產業大多朝向具較高的機械性質之β相鈦合金發展。因此，本文主要針對β相之鈦-20釩- 4鋁- 1錫合金(以下簡稱2041鈦合金)作一系列的分析，包括：機械性質、阻尼比、顯微結構分析、以及高爾夫球頭試作等。主要研究結果如下：

1.2041鈦合金經過780℃~1000℃固溶處理後，其晶粒尺寸大小介於7.9~25μm，其抗拉強度、

降服強度、延伸率和硬度，其範圍約在81.65~87.1 (kgf/mm2)、80.8~ 85.4(kgf/mm2)、

14.34~19.39%、HRc28~32之間，在長時間或較高溫度固溶處理後，由於較易形成麻田散鐵，

故強度有上升趨勢。經過800℃固溶與400℃~600℃時效處理後，其抗拉強度、降服強度則增加至128與120 (kgf/mm2)左右，而伸長率降至約4~6%，硬度則可高達HRc46.6。

2.2041鈦合金經由固溶處理後為完全β相結構或β相+α´的麻田散相混合結構，其中β相屬

於體心立方結構，晶格常數a=0.3365nm，而α´相為過飽和組織具六方最密堆積結構，晶格常數a=0.305nm，c=0.475nm，且在較高溫度固溶或較慢的冷卻速度時產生。合金經400℃~600℃時效處理後，其顯微結構基本上為β相基地與α´針狀組織和ω相顆粒之混合組織，其中ω相具六方最密堆積結構，晶格常數a=0.476nm(2½aβ)，c=0.291nm(3½aβ/2)，c/a=0.612。

3.2041鈦合金的在715±5℃以上為單相β相組織，比商用純Ti 低170℃。

4.2041鈦合金阻尼比(ξ)，依固溶或時效處理不同，其範圍大約介於0.0046~0.0031之間。楊

氏係數則介於54.24~72.54 GPa。

關鍵字：機械性質、顯微結構分析、高爾夫球、阻尼比

【Abstract】

Recently, for the well corrosion resistance and high strength-weight ratio, the Titanium alloy system has been widely used in the Golf industry, particularly are duplex Ti alloy (Ti-6Al-4V) and βTi alloy (Ti-15Al-5Zr-3Al) . Therefore, the main purposes of the present studies are to investigate the properties of Ti-20V-4Al-1Sn alloy with the higher strength-weight ratio, including the microstructure, mechanical

properties, damping ratio, Young modulus, and coefficient of response, etc. Based on the present studies, some results are described as following:

1. After being solution heat treatment at temperature in the range of 700 and 1000℃for various

time, the grain size, tensile strength, yield strength, elongation and hardness of the 2041 Ti alloy are in the range of the 7.9~25μm, 816.5~871.0 MPa, 808.0~854.0 MPa, 19.39~14.34% and HRc 28.0~32.0, respectively. When been aged at 400~600℃for various time, the tensile strength and yield strength of the alloy will increase to about 1280 MPa and 1200 MPa, and the hardness to HRc 46.6. However, the elongation would decrease to 4~6%.

2. The microstructure of the as-quenched specimen is either βphase or (β＋α’) phase, which

depended the cooling rate or the temperature of solution heat treatment. In addition, the lattice parameter of the β phase belonging to the body center cubic structure is a=0.3365 nm. And, the lattice parameter of theα’phase belonging to the hexagonal structure is a=0.305 nm, c=0.475 nm. Being aged, the microstructure of the present alloy are essentially β phase matrix contained some α’ and ω particles. Where theω particle is belonging to the hexagonal structure and its lattice parameter is a=0.476nm, c=0.291nm and c/a=0.612.

3. The microstructure of the present alloy would be a singleβ phase when the temperature being

above the 715℃. As compared with the commercial pure Titanium, the βphase transition temperature decreases about 150℃~160℃.

4. For various solution heat treatment and aging process, the damping ratio and Young modulus of

the 2041 Ti alloy are in the range of the 0.0046~0.0031 and 54.24~72.54 GPa, respectively.

Keywords: mechanical properties、microstructure、Golf、damping