Key points in sample preparation:
1、Cutting
Compared with other metals, titanium has a relatively low thermal conductivity, so water cooling must be used when cutting the sample to prevent local overheating. In addition, the cutting rate and feed rate of the cutting blade should be reduced. Materials are divided into soft and hard. In addition to silicon carbide cutting blades, resin diamond cutting blades with relatively weak bonding strength can also be used for cutting.
Silicon carbide resin cutting blade Resin diamond cutting blade
2、Mounting
Titanium and titanium alloys are generally mounted cold. In addition to the decomposition of the stable β phase, hot mounting may also produce hydrogen contamination, because hydrogen in the mounting material may diffuse into the sample under hot conditions, especially for samples with a high α phase content. Since the solubility of hydrogen in the α phase is extremely low, the solubility increases when the temperature rises, and the solubility decreases when cooling, resulting in the precipitation of fine and dispersed titanium hydride.
Titanium alloy mounting MC003 vacuum-free clear cold mounting kit
3、Grinding and polishing
Titanium alloys are usually prepared by mechanical polishing, which requires good control of pressure and speed.
The final polishing is usually repeated for a short period of time.
Since high-purity titanium is prone to surface deformation, electrolytic polishing is generally used to avoid the formation of a metamorphic layer.
The step of grinding & polishing |
Coarse Grinding |
Fine Grinding |
Diamond Coarse Polishing |
Diamond Fine Polishing |
Oxide polishing |
|
1 |
Surface |
|||||
2 |
Abrasive Granularity |
320# |
800#、1200#、4000# |
3μm |
1μm |
0.04μm |
3 |
Polishing/ Lubricant |
/ |
/ |
|||
4 |
Pressure |
30N |
25N |
25N |
20N |
15N |
5 |
Rotation Speed |
300 |
300 |
150 |
150 |
150 |
6 |
Time/min. |
1 |
2 |
3~5 |
2~3 |
2~5 |
The above recommended parameters are taken from: Preparation method of Ф30 mm titanium alloy sample with Ф250 mm working plate on automatic grinding and polishing machine Smoothneer-6.
钛合金通常采用化学侵蚀,侵蚀剂可根据合金成分、状态及要求来选择。在钛合金侵蚀用的试剂中,几乎都含有一定深度的氢氟酸和硝酸、氢氟酸起腐蚀作用,硝酸使腐蚀表面洁净光亮。试剂有水、酒精、甘油、乳酸等。氢氟酸水溶剂液试剂侵蚀速度快,难以控制侵蚀程度;酒精、甘油、乳酸等溶剂起缓蚀作用。
常用的钛及钛合金化学浸蚀试剂如下:
序号 |
名称 |
组成 |
试用范围 |
备注 |
1 |
氢氟酸硝酸水溶液 |
氢氟酸 2(体积) 硝酸 1(体积) 水 17(体积) |
钛及钛合金克氏试剂 (Kroll试剂) |
浸入法30~60s |
2 |
氢氟酸饱和草酸溶液 |
氢氟酸 4ml 饱和草酸溶液 196ml |
钛及钛合金 |
浸入法30~60s |
3 |
氢氟酸硝酸甘油 |
氢氟酸 5ml 硝酸 5ml 甘油 15ml |
钛及钛合金 |
浸入法30~60s |
钛和钛合金电解抛光液如下:
序号 |
配方 |
电解抛光条件 |
1 |
甲醇 630ml 丁醇 50ml 乙二醇丁醚 260ml 乙酸 2ml 高氯酸 60ml |
电压25V~40V,时间10s~30s |
2 |
高氯酸 78ml 蒸馏水 120ml 乙醇 700ml 乙二醇丁醚 100ml |
电压40V±1V,时间大约5s |
TA1板材退火后组织
TC4 3D打印钛合金
*以上图片,未得许可不得转载,否则将追究法律责任。
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