SECTION II

FABRICATION PROCEDURES

1, DU-6.5 W/O (Weight Percent) Nb ALLOY

This material was examined as a candidate liner material for several
"reasons. Previous experience with a cross-rolled, fine grained DU-6.5Nb
plate had shown the plate to have substantial ductility (38 percent elonga-
tion) with a grain size of American Society of Testing and Materials (ASTM)
6 to 6 1/2. As a gamma stabilized alloy at room temperature, it has a body
_ centered cubic structure with more slip systems than a DU alloy of orthor-
_hombic structure in the alpha phase.

An attempt was made to directly vacuum melt and cast this alloy and work
"the material in order to obtain a fine grain structure. Three castings were
made of 2 billets each. The billets were of 3 3/4-inch diameter by 20-inch

_ length and weighed approximately 150 pounds each.

The chemical analysis and melting conditions used for these attempts are
Shown in Table 1. Niobium plate had been used with success in previous nio-
_ bium alloy melts, and it was felt that by increasing the surface area of the
~ niobium, the material would more rapidly alloy with uranium. The objective
a was a lower superheat temperature and shorter length of time at temperature
in order to obtain a lower carbon content. In all attempts, unalloyed virgin
4 derby with low carbon, 10 to 40 parts per million (ppm), was selected for

3 alloying.

The niobium shot used in Melt UX9691 remained at the bottom of the cru-
cible where it was initially placed. The niobium never floated and was
observed as part of the crucible skull after the molten alloy was poured. A
low niobium content was the net result.

Milled niobium chips were used on the second attempt in Melt UX9764.
These floated to the top of the molten DU, partially sintered, and did not
alloy completely.



SECTION I

INTRODUCTION

1. OBJECTIVE OF THE PROGRAM

The objective of the efforts described in this report has been to evalu-
ate depleted uranium (DU) and several DU alloys for application to shaped
charge warheads. Since dynamic ductility of the material is an important
property affecting warhead performance, attempts were made to apply fabrica-
tion techniques using equipment available at the contractor's facility to
optimize these properties. If test firings of warheads fabricated from these
materials are successful, commercially available DU would be immediately
available to meet Air Force needs for a high density SFF warhead. If test
firings are unsuccessful or inconclusive, further efforts would be needed to
establish the minimum DU material requirements for successful warhead perfor-

mance.

2. SCOPE OF THE RESEARCH AND DEVELOPMENT PROGRAM

The scope was originally established as a 10-month effort to examine the
application of several DU candidate materials for shaped charge warheads. The
prime contractor was responsible for material selection, heat treatment, warm
working, production and static material property testing. Dynamic properties
data were obtained by Bill Cook of the Air Force Armament Laboratory from
Taylor Anvil specimens produced at the contractor's facility and test fired at
Denver Research Institute (DRI). Warhead firing fixtures of steel and plexi-
glass and DU liners of 4 different materials were fabricated according to
designs supplied by the Air Force.

Loading and test firing of the shaped charge warheads are being performed
by the Los Alamos Scientific Laboratories (LASL). Test analysis and firing
data will be supplied by LASL.



MELT AND CAST BILLETS

|

CUT AND MACHINE BILLETS TO
3. 1/2-INCH DIAMETER BY 3 1/2-INCH LENGTH

HIGH TEMPERATURE VACUUM OUTGAS
AND HOMOGENIZATION

|

CAN BILLETS IN 3 3/4-INCH DIAMETER
STEEL TUBE, WITH 4 1/2-INCH DIAMETER
END PLATES

|

WARM UPSET IN EXTRUSION PRESS
TO 4.555-INCH DIAMETER

|

MACHINE OFF THE STEEL CAN

i

CUT PANCAKES INTO MACHINING STOCK
FOR TEST SPECIMENS AND WARHEAD LINERS

|

SOLUTION TREAT UNDER
VACUUM AND WATER QUENCH

|

FINISH MACHINE

|

INSPECT AND/OR TEST

Figure 1. General Process Flow Chart for DU-6.5Nb,
DU-8Mo and DU-3/4Ti Alloys

=5 -



APPENDIX D
PUBLISHED REPORTS & EXCERPTS

AUTHORED BY

(copies of files on CDROM)

1979 USAF Alloy Development F0835-79-C-0267
1980 US Army Recycle Program DAAK10-80-C-0246
Foam Encapsulation
NMI Views Article

Depleted Uranium Test Range Fragment Reclamation F08635-82-C-0100
Storming Media Abstract, Final Report for work performed between 81-

82


Re... te lly a
vf : eas es

74 ;
APATL-TR-80-117

Depleted Uranium Alloys For Use

4 In Conventional Warheads

+

OCTOBER 1980

FINAL REPORT FOR PERIOD AUGUST 1979-SEPTEMBER 1980

Distribution limited to U.S. Government agencies only;
this report documents test and evaluation; distribution
limitation applied OCTOBER 1980 . Other requests for
this document must be referred to the Air Force

Armament Laboratory (DLJW) Eglin Air Force Base,
Florida 32542.

SUBJECT TO EXPORT CONTROL LAWS:

This document contains information for manufacturing or using munitions of war.
Export of the information contained herein, or release to foreign nationals within
the United States, without first obtaining an export license, is a violation of the
International Traffic in Arms Regulations. Such violation is subject to a penalty
of up to 2 years imprisonment and a fine of $100,000 under 22 U.S.C. 2778.
Include this notice with any reproduced portion of this document.

<5

Air Force Armament Laboratory Nios
AIR FORCE SYSTEMS COMMAND x UNITED STATES AIR FORCEXEGLIN AIR FORCE BASE, FLORIDA


- DU-8 W/O Mo ALLOY

This alloy is also a gamma stabilized alloy with a potential for use as a
liner material.

Melt UX0027 was cast for this program; however, the carbon content was
igher than was desirable. Melting procedures and chemical analysis are shown
in Table 3 for this alloy. Melt UX1043 was cast for another program at the
Contractor's facility. The carbon content was significantly lower for Melt
UX1043 than that for UX0027. Sufficient material for both programs was avail-
able from Melt UX1043, so it was decided to proceed with this lower carbon
alloy. Additional trace element analysis of Melt UX1043 is given in Table 4.

The processing sequence for the DU-8Mo alloy was essentially identical to
that used for the DU-6.5Nb alloy. The DU-8Mo was cast into a 4 1/4 inch diameter
mold. This billet was machined into slugs of 3 1/2-inch diameter by 3 1/2-inch
length. The remainder of the processing follows the same path as described for
the DU-6.5Nb alloy and the general process flow chart presented in Figure 1.

4. DU-0.75 W/O Ti ALLOY

Excellent ductility has been achieved with this alloy during the past few
years as a result of improved chemistry and heat treatment studies aimed at
improving the toughness of this material for withstanding firing forces placed
on kinetic energy projectiles.

The alloy was obtained from material prepared for the Army's M774 KE pro-
jectile production. There is a tight chemical specification for low carbon,
‘iron, and hydrogen in this material. Table 5 shows the standard melting and
casting conditions for this alloy as well as the chemistry of Lot 92, Billet 9,
from which material for test specimens and liners was obtained.

The billet was 4 1/2 inches in diameter by 20 inches long. Two slugs from
the bottom of the billet were machined to a 3 1/2-inch diameter by 3 1/2-inch
length. The slugs were then processed according to the general flow chart of
Figure 1 and the same conditions used for the DU-6.5Nb alloy previously des-
cribed.



AFATL-TR-80-117

DEPLETED URANIUM ALLOYS FOR USE IN CONVENTIONAL WARHEADS

October 1980

Final Report for Period August 1979 - September 1980

Distribution limited to U.S. Government agencies only; this report
documents test and evaluation; distribution limitation applied
October 1980. Other requests for this document must be referred to
the Air Force Armament Laboratory (DLUW), Eglin Air Force Base,
Florida 32542.

Prepared for

United States Air Force
Armament Development & Test Center

Eglin Air Force Base
Florida 32542