內部 淬裂......................
本帖最后由 leomet 于 2014-12-20 14:15 编辑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? 真的学习了!!虽然有些看不懂 H13 熱鍛模破裂.........
有沒有人願意把文章搬上版面? 本帖最后由 leomet 于 2014-9-28 12:48 编辑
leomet 发表于 2014-7-20 16:27 static/image/common/back.gif
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?mod=viewthread&tid=166559&pid=1566389&page=1&extra=page%3D1#pid1566389
本帖最后由 leomet 于 2015-10-21 08:27 编辑
leomet 发表于 2014-9-23 19:58 static/image/common/back.gif
420 J2
http://www.rclbbs.com/forum.php?mod=viewthread&tid=166559&pid=1566389&page=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.
本帖最后由 leomet 于 2014-9-29 07:27 编辑
這材料 1030C x 15 分鐘, 淬後未回火. as-quenched.蝕後輕拋兩圈. 拋光 大倍數下.............. 15分鐘時間偏短.固溶的碳化物太少了! 1030C x 30分鐘; 200C x 2hr x 2 次 SEM photos for raw material. 本帖最后由 leomet 于 2014-9-26 19:12 编辑
1030C 15 min. as-quenched,
Black pits are carbide pits. carbide particleschipped off
because I performed etch polishing. Too much polishing,
本帖最后由 leomet 于 2014-9-28 16:18 编辑
This very sample under discussion.
Take a look at the giant grains ! 與釘書針合照的............... 比較此同問題的 H13 鍛塊 本帖最后由 leomet 于 2014-10-11 21:16 编辑
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. 本帖最后由 leomet 于 2015-6-8 09:31 编辑
The precipitation phenomenon applies to all alloy systems.
不限用於鋁合金. 本帖最后由 leomet 于 2014-10-11 21:01 编辑
Zig-zag precipitates is also an interesting re-crystalisation behavior. SUS 420J2 原材料.
Those 平行線條.
Tell me what they are if you say they are not twins. More.............................