失效及缺陷组织照片

fyt66

从未看见过如此多的、精美的金相图片，收藏学习了，谢谢

leomet

Shown below is a photo taken by me when I was 33--I am 63 now. I hope you guys enjoy it.
It shows the kind of quench crack that you see only once in a blue moon.

當年送檢者說: 打硬度就合格, 為何几乎無強度?

wufangq

真的学习了！！虽然有些看不懂

leomet

H13 熱鍛模破裂.........

有沒有人願意把文章搬上版面?

leomet

leomet 发表于 2014-7-20 16:27
H13 熱鍛模破裂.........

有沒有人願意把文章搬上版面?

420 J2  
http://www.rclbbs.com/forum.php? ... page%3D1#pid1566389

leomet

leomet 发表于 2014-9-23 19:58
420 J2  
http://www.rclbbs.com/forum.php? ... e=1&extra=page% ...

美圖分享.............

從下往上看, aa1~aa3 碳化物微粒嚴重偏析 都往晶界偏聚.彩帶區碳化物微粒密度分佈偏高.內部淡色島嶼碳化物微粒密度分佈偏低.巨晶粒徑 >400um. 是鍛塊球化處理後形成的. 偏析則是鑄錠均質熱處理未做好.

這種原材料缺陷, 大模塊才會遇到. 因鑄錠重量動輒几十噸. 超溫鍛造後的降溫過程,仍處FCC狀態, 有動態的再結晶 + 析出行為........

所以會有双晶帶Twin.

leomet

這材料 1030C x 15 分鐘, 淬後未回火. as-quenched.蝕後輕拋兩圈.

leomet

拋光 大倍數下..............

leomet

15分鐘時間偏短.固溶的碳化物太少了!

leomet

1030C x 30分鐘; 200C x 2hr x 2 次

leomet

SEM photos for raw material.

leomet

1030C 15 min. as-quenched,

Black pits are carbide pits. carbide particles  chipped off
because I performed etch polishing. Too much polishing,

leomet

This very sample under discussion.

Take a look at the giant grains !

leomet

與釘書針合照的...............

leomet

比較此同問題的 H13 鍛塊

leomet

More photos with interesting features.

Things to ponder: Why there always is a carbide-depleted zone, or carbide-LESS zone,
along this straight-line carbide?
Here, carbide particles = precipitates.

leomet

The precipitation phenomenon applies to all alloy systems.
不限用於鋁合金.

leomet

Zig-zag precipitates is also an interesting re-crystalisation behavior.

leomet

SUS 420J2 原材料.

Those 平行線條.
Tell me what they are if you say they are not twins.

leomet

More.............................